Address 'make sc_error_message_uppercase' failures.

* m4/output.c (m4_freeze_diversions): Silence false positive.
* src/main.c (main): Use 'warning', not 'Warning', in messages.
* m4/utility.c (m4_verror_at_line): Likewise.
* doc/m4.texinfo (Operation modes, Macro Arguments, Undefine)
(Defn, Pushdef, Indir, Builtin, Ifdef, Ifelse, Dumpdef, Trace)
(Debuglen, Debugfile, Dnl, Changeresyntax, Standard Modules)
(Index macro, Regexp, Substr, Translit, Patsubst, Format, Incr)
(Eval, Mkstemp, Syncoutput, Improved forloop)
(Improved fatal_error): Adjust expected output.
* tests/builtins.at (define, mkdtemp, mkstemp): Likewise.
* tests/freeze.at (loading format 1, reloading unknown builtin):
Likewise.
* tests/macros.at (Arity and defn, 'Arity, defn, and freeze')
(pushdef/popdef): Likewise.
* tests/null.err: Likewise.
* tests/options.at (deprecated options, POSIXLY_CORRECT)
(--fatal-warnings, --regexp-syntax, --syncoutput): Likewise.
* tests/others.at (nul character, stdin seekable): Likewise.
* tests/modules.at (AT_CHECK_M4_MODTEST, modules: text):
Likewise.

Signed-off-by: Eric Blake <ebb9@byu.net>

12 files changed, 177 insertions, 155 deletions

diff --git a/ChangeLog b/ChangeLog
index b4786403..b3175771 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,27 @@
 2010-01-07  Eric Blake  <ebb9@byu.net>
 
+	Address 'make sc_error_message_uppercase' failures.
+	* m4/output.c (m4_freeze_diversions): Silence false positive.
+	* src/main.c (main): Use 'warning', not 'Warning', in messages.
+	* m4/utility.c (m4_verror_at_line): Likewise.
+	* doc/m4.texinfo (Operation modes, Macro Arguments, Undefine)
+	(Defn, Pushdef, Indir, Builtin, Ifdef, Ifelse, Dumpdef, Trace)
+	(Debuglen, Debugfile, Dnl, Changeresyntax, Standard Modules)
+	(Index macro, Regexp, Substr, Translit, Patsubst, Format, Incr)
+	(Eval, Mkstemp, Syncoutput, Improved forloop)
+	(Improved fatal_error): Adjust expected output.
+	* tests/builtins.at (define, mkdtemp, mkstemp): Likewise.
+	* tests/freeze.at (loading format 1, reloading unknown builtin):
+	Likewise.
+	* tests/macros.at (Arity and defn, 'Arity, defn, and freeze')
+	(pushdef/popdef): Likewise.
+	* tests/null.err: Likewise.
+	* tests/options.at (deprecated options, POSIXLY_CORRECT)
+	(--fatal-warnings, --regexp-syntax, --syncoutput): Likewise.
+	* tests/others.at (nul character, stdin seekable): Likewise.
+	* tests/modules.at (AT_CHECK_M4_MODTEST, modules: text):
+	Likewise.
+
 	Address 'make sc_cast_of_argument_to_free' failures.
 	* m4/m4private.h (DELETE): Adjust comment and fix parentheses.
 	* m4/m4.c (m4_delete): Use it to avoid warning.
diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index 6cb1472e..2d4a81b9 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -661,7 +661,7 @@ a warning.
 @example
 $ @kbd{m4}
 defn(`oops')
-@error{}m4:stdin:1: Warning: defn: undefined macro `oops'
+@error{}m4:stdin:1: warning: defn: undefined macro `oops'
 @result{}
 ^D
 @end example
@@ -691,7 +691,7 @@ $ @kbd{echo $?}
 @example
 $ @kbd{m4 -E -d}
 defn(`oops')
-@error{}m4:stdin:1: Warning: defn: undefined macro `oops'
+@error{}m4:stdin:1: warning: defn: undefined macro `oops'
 @result{}
 ^D
 @end example
@@ -1693,12 +1693,12 @@ defined macros, there is no check of the number of arguments given.
 @example
 $ @kbd{m4}
 index(`abc')
-@error{}m4:stdin:1: Warning: index: too few arguments: 1 < 2
+@error{}m4:stdin:1: warning: index: too few arguments: 1 < 2
 @result{}0
 index(`abc',)
 @result{}0
 index(`abc', `b', `0', `ignored')
-@error{}m4:stdin:3: Warning: index: extra arguments ignored: 4 > 3
+@error{}m4:stdin:3: warning: index: extra arguments ignored: 4 > 3
 @result{}1
 @end example
 
@@ -2254,7 +2254,7 @@ m4}).
 @example
 $ @kbd{m4}
 undefine(`a')
-@error{}m4:stdin:1: Warning: undefine: undefined macro `a'
+@error{}m4:stdin:1: warning: undefine: undefined macro `a'
 @result{}
 debugmode(`-d')
 @result{}
@@ -2392,7 +2392,7 @@ $ @kbd{m4 -d}
 defn(`defn')
 @result{}
 define(defn(`divnum'), `cannot redefine a builtin token')
-@error{}m4:stdin:2: Warning: define: invalid macro name ignored
+@error{}m4:stdin:2: warning: define: invalid macro name ignored
 @result{}
 divnum
 @result{}0
@@ -2407,36 +2407,36 @@ mydivnum
 define(`', `empty-$1')
 @result{}
 defn(defn(`divnum'))
-@error{}m4:stdin:9: Warning: defn: invalid macro name ignored
+@error{}m4:stdin:9: warning: defn: invalid macro name ignored
 @result{}
 pushdef(defn(`divnum'), `oops')
-@error{}m4:stdin:10: Warning: pushdef: invalid macro name ignored
+@error{}m4:stdin:10: warning: pushdef: invalid macro name ignored
 @result{}
 traceon(defn(`divnum'))
-@error{}m4:stdin:11: Warning: traceon: invalid macro name ignored
+@error{}m4:stdin:11: warning: traceon: invalid macro name ignored
 @result{}
 indir(defn(`divnum'), `string')
-@error{}m4:stdin:12: Warning: indir: invalid macro name ignored
+@error{}m4:stdin:12: warning: indir: invalid macro name ignored
 @result{}
 indir(`', `string')
 @result{}empty-string
 traceoff(defn(`divnum'))
-@error{}m4:stdin:14: Warning: traceoff: invalid macro name ignored
+@error{}m4:stdin:14: warning: traceoff: invalid macro name ignored
 @result{}
 popdef(defn(`divnum'))
-@error{}m4:stdin:15: Warning: popdef: invalid macro name ignored
+@error{}m4:stdin:15: warning: popdef: invalid macro name ignored
 @result{}
 dumpdef(defn(`divnum'))
-@error{}m4:stdin:16: Warning: dumpdef: invalid macro name ignored
+@error{}m4:stdin:16: warning: dumpdef: invalid macro name ignored
 @result{}
 undefine(defn(`divnum'))
-@error{}m4:stdin:17: Warning: undefine: invalid macro name ignored
+@error{}m4:stdin:17: warning: undefine: invalid macro name ignored
 @result{}
 dumpdef(`')
 @error{}:@tabchar{}`empty-$1'
 @result{}
 m4symbols(defn(`divnum'))
-@error{}m4:stdin:19: Warning: m4symbols: invalid macro name ignored
+@error{}m4:stdin:19: warning: m4symbols: invalid macro name ignored
 @result{}
 define(`foo', `define(`$1', $2)')dnl
 foo(`bar', defn(`divnum'))
@@ -2457,7 +2457,7 @@ builtin token does not occur in isolation.  A future version of
 @example
 $ @kbd{m4 -d}
 defn(`foo')
-@error{}m4:stdin:1: Warning: defn: undefined macro `foo'
+@error{}m4:stdin:1: warning: defn: undefined macro `foo'
 @result{}
 debugmode(`-d')
 @result{}
@@ -2472,25 +2472,25 @@ defn(`a', `divnum', `a')
 @result{}AA
 define(`mydivnum', defn(`divnum', `divnum'))mydivnum
 @error{}m4trace: -2- defn(`divnum', `divnum') -> `<divnum><divnum>'
-@error{}m4:stdin:7: Warning: define: cannot concatenate builtins
+@error{}m4:stdin:7: warning: define: cannot concatenate builtins
 @error{}m4trace: -1- define(`mydivnum', `<divnum><divnum>') -> `'
 @result{}
 traceoff(`defn', `define')dumpdef(`mydivnum')
 @error{}mydivnum:@tabchar{}`'
 @result{}
 define(`mydivnum', defn(`divnum')defn(`divnum'))mydivnum
-@error{}m4:stdin:9: Warning: define: cannot concatenate builtins
+@error{}m4:stdin:9: warning: define: cannot concatenate builtins
 @result{}
 define(`mydivnum', defn(`divnum')`a')mydivnum
-@error{}m4:stdin:10: Warning: define: cannot concatenate builtins
+@error{}m4:stdin:10: warning: define: cannot concatenate builtins
 @result{}A
 define(`mydivnum', `a'defn(`divnum'))mydivnum
-@error{}m4:stdin:11: Warning: define: cannot concatenate builtins
+@error{}m4:stdin:11: warning: define: cannot concatenate builtins
 @result{}A
 define(`q', ``$@@'')
 @result{}
 define(`foo', q(`a', defn(`divnum')))foo
-@error{}m4:stdin:13: Warning: define: cannot concatenate builtins
+@error{}m4:stdin:13: warning: define: cannot concatenate builtins
 @result{}a,
 ifdef(`foo', `yes', `no')
 @result{}yes
@@ -2607,7 +2607,7 @@ define(`a', `1')
 popdef
 @result{}popdef
 popdef(`a', `a')
-@error{}m4:stdin:3: Warning: popdef: undefined macro `a'
+@error{}m4:stdin:3: warning: popdef: undefined macro `a'
 @result{}
 debugmode(`-d')
 @result{}
@@ -2782,7 +2782,7 @@ f(define(`f', `2'))
 indir(`f', define(`f', `3'))
 @result{}3
 indir(`f', undefine(`f'))
-@error{}m4:stdin:4: Warning: indir: undefined macro `f'
+@error{}m4:stdin:4: warning: indir: undefined macro `f'
 @result{}
 debugmode(`-d')
 @result{}
@@ -2798,17 +2798,17 @@ string.
 @example
 $ @kbd{m4 -d}
 indir(defn(`defn'), `divnum')
-@error{}m4:stdin:1: Warning: indir: invalid macro name ignored
+@error{}m4:stdin:1: warning: indir: invalid macro name ignored
 @result{}
 indir(`define', defn(`defn'), `divnum')
-@error{}m4:stdin:2: Warning: define: invalid macro name ignored
+@error{}m4:stdin:2: warning: define: invalid macro name ignored
 @result{}
 indir(`define', `foo', defn(`divnum'))
 @result{}
 foo
 @result{}0
 indir(`divert', defn(`foo'))
-@error{}m4:stdin:5: Warning: divert: empty string treated as 0
+@error{}m4:stdin:5: warning: divert: empty string treated as 0
 @result{}
 @end example
 
@@ -2822,7 +2822,7 @@ odd', defn(`divnum'))
 @result{}
 indir(`%%:\
 odd', `extra')
-@error{}m4:stdin:3: Warning: %%\:\\\nodd: extra arguments ignored: 1 > 0
+@error{}m4:stdin:3: warning: %%\:\\\nodd: extra arguments ignored: 1 > 0
 @result{}0
 @end example
 
@@ -2893,10 +2893,10 @@ $ @kbd{m4 -P}
 m4_builtin(`divnum')
 @result{}0
 m4_builtin(`m4_divnum')
-@error{}m4:stdin:2: Warning: m4_builtin: undefined builtin `m4_divnum'
+@error{}m4:stdin:2: warning: m4_builtin: undefined builtin `m4_divnum'
 @result{}
 m4_indir(`divnum')
-@error{}m4:stdin:3: Warning: m4_indir: undefined macro `divnum'
+@error{}m4:stdin:3: warning: m4_indir: undefined macro `divnum'
 @result{}
 m4_indir(`m4_divnum')
 @result{}0
@@ -2915,20 +2915,20 @@ as though empty strings had been passed as the required arguments.
 builtin
 @result{}builtin
 builtin()
-@error{}m4:stdin:2: Warning: builtin: undefined builtin `'
+@error{}m4:stdin:2: warning: builtin: undefined builtin `'
 @result{}
 builtin(`builtin')
-@error{}m4:stdin:3: Warning: builtin: too few arguments: 0 < 1
+@error{}m4:stdin:3: warning: builtin: too few arguments: 0 < 1
 @result{}
 builtin(`builtin',)
-@error{}m4:stdin:4: Warning: builtin: undefined builtin `'
+@error{}m4:stdin:4: warning: builtin: undefined builtin `'
 @result{}
 builtin(`builtin', ``'
 ')
-@error{}m4:stdin:5: Warning: builtin: undefined builtin ``\'\n'
+@error{}m4:stdin:5: warning: builtin: undefined builtin ``\'\n'
 @result{}
 indir(`index')
-@error{}m4:stdin:7: Warning: index: too few arguments: 0 < 2
+@error{}m4:stdin:7: warning: index: too few arguments: 0 < 2
 @result{}0
 @end example
 
@@ -2985,7 +2985,7 @@ traceoff
 changequote(`[', `]')
 @result{}
 defn1([foo])
-@error{}m4:stdin:11: Warning: builtin: undefined builtin ``defn\''
+@error{}m4:stdin:11: warning: builtin: undefined builtin ``defn\''
 @result{}
 defn2([foo])
 @result{}bar
@@ -2996,7 +2996,7 @@ defn1([foo])
 changequote
 @result{}
 defn1(`foo')
-@error{}m4:stdin:16: Warning: builtin: undefined builtin `[defn]'
+@error{}m4:stdin:16: warning: builtin: undefined builtin `[defn]'
 @result{}
 @end example
 
@@ -3069,7 +3069,7 @@ define(`foo', `')
 ifdef(`foo', ``foo' is defined', ``foo' is not defined')
 @result{}foo is defined
 ifdef(`no_such_macro', `yes', `no', `extra argument')
-@error{}m4:stdin:4: Warning: ifdef: extra arguments ignored: 4 > 3
+@error{}m4:stdin:4: warning: ifdef: extra arguments ignored: 4 > 3
 @result{}no
 @end example
 
@@ -3081,7 +3081,7 @@ generated by @code{defn} (@pxref{Defn}) that occur in either
 define(`', `empty')
 @result{}
 ifdef(defn(`defn'), `yes', `no')
-@error{}m4:stdin:2: Warning: ifdef: invalid macro name ignored
+@error{}m4:stdin:2: warning: ifdef: invalid macro name ignored
 @result{}no
 define(`foo', ifdef(`divnum', defn(`divnum'), `undefined'))
 @result{}
@@ -3129,7 +3129,7 @@ case, the warning about missing arguments is never triggered.
 ifelse(`some comments')
 @result{}
 ifelse(`foo', `bar')
-@error{}m4:stdin:2: Warning: ifelse: too few arguments: 2 < 3
+@error{}m4:stdin:2: warning: ifelse: too few arguments: 2 < 3
 @result{}
 @end example
 
@@ -3181,14 +3181,14 @@ calls for an example:
 
 @example
 ifelse(`foo', `bar', `third', `gnu', `gnats')
-@error{}m4:stdin:1: Warning: ifelse: extra arguments ignored: 5 > 4
+@error{}m4:stdin:1: warning: ifelse: extra arguments ignored: 5 > 4
 @result{}gnu
 ifelse(`foo', `bar', `third', `gnu', `gnats', `sixth')
 @result{}
 ifelse(`foo', `bar', `third', `gnu', `gnats', `sixth', `seventh')
 @result{}seventh
 ifelse(`foo', `bar', `3', `gnu', `gnats', `6', `7', `8')
-@error{}m4:stdin:4: Warning: ifelse: extra arguments ignored: 8 > 7
+@error{}m4:stdin:4: warning: ifelse: extra arguments ignored: 8 > 7
 @result{}7
 @end example
 
@@ -4117,7 +4117,7 @@ f(popdef(`f')dumpdef(`f'))
 @error{}f:@tabchar{}``$0'1'
 @result{}f2
 f(popdef(`f')dumpdef(`f'))
-@error{}m4:stdin:3: Warning: dumpdef: undefined macro `f'
+@error{}m4:stdin:3: warning: dumpdef: undefined macro `f'
 @result{}f1
 debugmode(`-d')
 @result{}
@@ -4241,17 +4241,17 @@ traceon(`foo')
 foo
 @result{}foo
 defn(`foo')
-@error{}m4:stdin:4: Warning: defn: undefined macro `foo'
+@error{}m4:stdin:4: warning: defn: undefined macro `foo'
 @result{}
 undefine(`foo')
-@error{}m4:stdin:5: Warning: undefine: undefined macro `foo'
+@error{}m4:stdin:5: warning: undefine: undefined macro `foo'
 @result{}
 pushdef(`foo')
 @result{}
 popdef(`foo')
 @result{}
 popdef(`foo')
-@error{}m4:stdin:8: Warning: popdef: undefined macro `foo'
+@error{}m4:stdin:8: warning: popdef: undefined macro `foo'
 @result{}
 define(`foo', `bar')
 @result{}
@@ -4263,7 +4263,7 @@ undefine(`foo')
 ifdef(`foo', `yes', `no')
 @result{}no
 indir(`foo')
-@error{}m4:stdin:13: Warning: indir: undefined macro `foo'
+@error{}m4:stdin:13: warning: indir: undefined macro `foo'
 @result{}
 define(`foo', `blah')
 @result{}
@@ -4673,7 +4673,7 @@ Also, the special tokens for builtin functions are not truncated.
 @example
 $ @kbd{m4 -d -l 6 -t echo -t defn}
 debuglen(`oops')
-@error{}m4:stdin:1: Warning: debuglen: non-numeric argument `oops'
+@error{}m4:stdin:1: warning: debuglen: non-numeric argument `oops'
 @result{}
 define(`echo', `$@@')
 @result{}
@@ -4732,13 +4732,13 @@ $ @kbd{m4 -d}
 traceon(`divnum')
 @result{}
 divnum(`extra')
-@error{}m4:stdin:2: Warning: divnum: extra arguments ignored: 1 > 0
+@error{}m4:stdin:2: warning: divnum: extra arguments ignored: 1 > 0
 @error{}m4trace: -1- divnum(`extra') -> `0'
 @result{}0
 debugfile()
 @result{}
 divnum(`extra')
-@error{}m4:stdin:4: Warning: divnum: extra arguments ignored: 1 > 0
+@error{}m4:stdin:4: warning: divnum: extra arguments ignored: 1 > 0
 @result{}0
 debugfile
 @result{}
@@ -4865,7 +4865,7 @@ next newline, on whatever line containing it, will still be discarded.
 @example
 dnl(`args are ignored, but side effects occur',
 define(`foo', `like this')) while this text is ignored: undefine(`foo')
-@error{}m4:stdin:1: Warning: dnl: extra arguments ignored: 2 > 0
+@error{}m4:stdin:1: warning: dnl: extra arguments ignored: 2 > 0
 See how `foo' was defined, foo?
 @result{}See how foo was defined, like this?
 @end example
@@ -4880,7 +4880,7 @@ m4wrap(`m4wrap(`2 hi
 define(`hi', `HI')
 @result{}
 ^D
-@error{}m4:stdin:1: Warning: dnl: end of file treated as newline
+@error{}m4:stdin:1: warning: dnl: end of file treated as newline
 @result{}0 HI 2 HI
 @end example
 
@@ -5361,7 +5361,7 @@ changeresyntax(`GNU-m4')
 changeresyntax(`Gnu_M4')
 @result{}
 changeresyntax(`unknown')
-@error{}m4:stdin:4: Warning: changeresyntax: bad syntax-spec: `unknown'
+@error{}m4:stdin:4: warning: changeresyntax: bad syntax-spec: `unknown'
 @result{}
 @end example
 
@@ -6799,7 +6799,7 @@ __gnu__-__traditional__
 ifdef(`__gnu__', `Extensions are active', `Minimal features')
 @result{}Extensions are active
 __gnu__(`ignored')
-@error{}m4:stdin:3: Warning: __gnu__: extra arguments ignored: 1 > 0
+@error{}m4:stdin:3: warning: __gnu__: extra arguments ignored: 1 > 0
 @result{}
 @end example
 
@@ -6893,7 +6893,7 @@ contrast this with an empty @var{substring}.
 
 @example
 index(`abc')
-@error{}m4:stdin:1: Warning: index: too few arguments: 1 < 2
+@error{}m4:stdin:1: warning: index: too few arguments: 1 < 2
 @result{}0
 index(`abc', `')
 @result{}0
@@ -6973,13 +6973,13 @@ Here are some more examples on the handling of backslash:
 regexp(`abc', `\(b\)', `\\\10\a')
 @result{}\b0a
 regexp(`abc', `b', `\1\')
-@error{}m4:stdin:2: Warning: regexp: sub-expression 1 not present
-@error{}m4:stdin:2: Warning: regexp: trailing \ ignored in replacement
+@error{}m4:stdin:2: warning: regexp: sub-expression 1 not present
+@error{}m4:stdin:2: warning: regexp: trailing \ ignored in replacement
 @result{}
 regexp(`abc', `\(\(d\)?\)\(c\)', `\1\2\3\4\5\6')
-@error{}m4:stdin:3: Warning: regexp: sub-expression 4 not present
-@error{}m4:stdin:3: Warning: regexp: sub-expression 5 not present
-@error{}m4:stdin:3: Warning: regexp: sub-expression 6 not present
+@error{}m4:stdin:3: warning: regexp: sub-expression 4 not present
+@error{}m4:stdin:3: warning: regexp: sub-expression 5 not present
+@error{}m4:stdin:3: warning: regexp: sub-expression 6 not present
 @result{}c
 @end example
 
@@ -6988,7 +6988,7 @@ contrast this with an empty @var{regexp} argument.
 
 @example
 regexp(`abc')
-@error{}m4:stdin:1: Warning: regexp: too few arguments: 1 < 2
+@error{}m4:stdin:1: warning: regexp: too few arguments: 1 < 2
 @result{}0
 regexp(`abc', `')
 @result{}0
@@ -7075,7 +7075,7 @@ other hand, selecting a @var{from} or @var{length} that lies beyond
 
 @example
 substr(`abc')
-@error{}m4:stdin:1: Warning: substr: too few arguments: 1 < 2
+@error{}m4:stdin:1: warning: substr: too few arguments: 1 < 2
 @result{}abc
 substr(`abc', `')
 @result{}abc
@@ -7132,10 +7132,10 @@ substr(`abcde', `-3', `-4', `f')
 substr(`abcde', `-6', `1', `f')
 @result{}fabcde
 substr(`abcde', `-7', `1', `f')
-@error{}m4:stdin:5: Warning: substr: substring out of range
+@error{}m4:stdin:5: warning: substr: substring out of range
 @result{}
 substr(`abcde', `6', `', `f')
-@error{}m4:stdin:6: Warning: substr: substring out of range
+@error{}m4:stdin:6: warning: substr: substring out of range
 @result{}
 @end example
 
@@ -7288,7 +7288,7 @@ Omitting @var{chars} evokes a warning, but still produces output.
 
 @example
 translit(`abc')
-@error{}m4:stdin:1: Warning: translit: too few arguments: 1 < 2
+@error{}m4:stdin:1: warning: translit: too few arguments: 1 < 2
 @result{}abc
 @end example
 
@@ -7351,7 +7351,7 @@ patsubst(`GNUs not Unix', `\w+', `(\&)')
 patsubst(`GNUs not Unix', `[A-Z][a-z]+')
 @result{}GN not@w{ }
 patsubst(`GNUs not Unix', `not', `NOT\')
-@error{}m4:stdin:6: Warning: patsubst: trailing \ ignored in replacement
+@error{}m4:stdin:6: warning: patsubst: trailing \ ignored in replacement
 @result{}GNUs NOT Unix
 @end example
 
@@ -7443,7 +7443,7 @@ contrast this with an empty @var{regexp} argument.
 
 @example
 patsubst(`abc')
-@error{}m4:stdin:1: Warning: patsubst: too few arguments: 1 < 2
+@error{}m4:stdin:1: warning: patsubst: too few arguments: 1 < 2
 @result{}abc
 patsubst(`abc', `')
 @result{}abc
@@ -7544,14 +7544,14 @@ Likewise, escape sequences are not yet recognized.
 
 @example
 format(`%p', `0')
-@error{}m4:stdin:1: Warning: format: unrecognized specifier in `%p'
+@error{}m4:stdin:1: warning: format: unrecognized specifier in `%p'
 @result{}p
 format(`%*d', `')
-@error{}m4:stdin:2: Warning: format: empty string treated as 0
-@error{}m4:stdin:2: Warning: format: too few arguments: 2 < 3
+@error{}m4:stdin:2: warning: format: empty string treated as 0
+@error{}m4:stdin:2: warning: format: too few arguments: 2 < 3
 @result{}0
 format(`%.1f', `2a')
-@error{}m4:stdin:3: Warning: format: non-numeric argument `2a'
+@error{}m4:stdin:3: warning: format: non-numeric argument `2a'
 @result{}2.0
 @end example
 
@@ -7594,10 +7594,10 @@ incr(`4')
 decr(`7')
 @result{}6
 incr()
-@error{}m4:stdin:3: Warning: incr: empty string treated as 0
+@error{}m4:stdin:3: warning: incr: empty string treated as 0
 @result{}1
 decr()
-@error{}m4:stdin:4: Warning: decr: empty string treated as 0
+@error{}m4:stdin:4: warning: decr: empty string treated as 0
 @result{}-1
 @end example
 
@@ -7707,23 +7707,23 @@ eval(`(1 | 1) ^ 1')
 eval(`+ + - ~ ! ~ 0')
 @result{}1
 eval(`++0')
-@error{}m4:stdin:8: Warning: eval: invalid operator: `++0'
+@error{}m4:stdin:8: warning: eval: invalid operator: `++0'
 @result{}
 eval(`1 = 1')
-@error{}m4:stdin:9: Warning: eval: invalid operator: `1 = 1'
+@error{}m4:stdin:9: warning: eval: invalid operator: `1 = 1'
 @result{}
 eval(`0 |= 1')
-@error{}m4:stdin:10: Warning: eval: invalid operator: `0 |= 1'
+@error{}m4:stdin:10: warning: eval: invalid operator: `0 |= 1'
 @result{}
 eval(`2 || 1 / 0')
 @result{}1
 eval(`0 || 1 / 0')
-@error{}m4:stdin:12: Warning: eval: divide by zero: `0 || 1 / 0'
+@error{}m4:stdin:12: warning: eval: divide by zero: `0 || 1 / 0'
 @result{}
 eval(`0 && 1 % 0')
 @result{}0
 eval(`2 && 1 % 0')
-@error{}m4:stdin:14: Warning: eval: modulo by zero: `2 && 1 % 0'
+@error{}m4:stdin:14: warning: eval: modulo by zero: `2 && 1 % 0'
 @result{}
 @end example
 
@@ -7751,9 +7751,9 @@ eval(`2 ** 0')
 @result{}1
 eval(`0 ** 0')
 @result{}
-@error{}m4:stdin:5: Warning: eval: divide by zero: `0 ** 0'
+@error{}m4:stdin:5: warning: eval: divide by zero: `0 ** 0'
 eval(`4 ** -2')
-@error{}m4:stdin:6: Warning: eval: negative exponent: `4 ** -2'
+@error{}m4:stdin:6: warning: eval: negative exponent: `4 ** -2'
 @result{}
 eval(`2 || 4 ** -2')
 @result{}1
@@ -7816,7 +7816,7 @@ square(square(`5')` + 1')
 define(`foo', `666')
 @result{}
 eval(`foo / 6')
-@error{}m4:stdin:11: Warning: eval: bad expression: `foo / 6'
+@error{}m4:stdin:11: warning: eval: bad expression: `foo / 6'
 @result{}
 eval(foo / 6)
 @result{}111
@@ -7888,16 +7888,16 @@ eval(`10', `', `0')
 eval(`10', `16')
 @result{}a
 eval(`1', `37')
-@error{}m4:stdin:9: Warning: eval: radix out of range: 37
+@error{}m4:stdin:9: warning: eval: radix out of range: 37
 @result{}
 eval(`1', , `-1')
-@error{}m4:stdin:10: Warning: eval: negative width: -1
+@error{}m4:stdin:10: warning: eval: negative width: -1
 @result{}
 eval()
-@error{}m4:stdin:11: Warning: eval: empty string treated as 0
+@error{}m4:stdin:11: warning: eval: empty string treated as 0
 @result{}0
 eval(` ')
-@error{}m4:stdin:12: Warning: eval: empty string treated as 0
+@error{}m4:stdin:12: warning: eval: empty string treated as 0
 @result{}0
 define(`a', `hi')eval(` 10 ', `16')
 @result{}hi
@@ -8335,7 +8335,7 @@ $ @kbd{m4}
 define(`tmp', `oops')
 @result{}
 maketemp(`/tmp/fooXXXXXX')
-@error{}m4:stdin:1: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:1: warning: maketemp: recommend using mkstemp instead
 @result{}/tmp/fooa07346
 ifdef(`mkstemp', `define(`maketemp', defn(`mkstemp'))',
       `define(`mkstemp', defn(`maketemp'))dnl
@@ -8351,7 +8351,7 @@ mkstemp(`doc')
 @example
 $ @kbd{m4 --safer}
 maketemp(`/tmp/fooXXXXXX')
-@error{}m4:stdin:1: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:1: warning: maketemp: recommend using mkstemp instead
 @error{}m4:stdin:1: maketemp: disabled by --safer
 @result{}
 mkstemp(`/tmp/fooXXXXXX')
@@ -8379,12 +8379,12 @@ define(`foo', `errprint(`oops')')
 syscmd(`rm -f foo-??????')sysval
 @result{}0
 define(`file1', maketemp(`foo-XXXXXX'))dnl
-@error{}m4:stdin:3: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:3: warning: maketemp: recommend using mkstemp instead
 ifelse(esyscmd(`echo \` foo-?????? \''), `foo-??????',
        `no file', `created')
 @result{}created
 define(`file2', maketemp(`foo-XX'))dnl
-@error{}m4:stdin:6: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:6: warning: maketemp: recommend using mkstemp instead
 define(`file3', mkstemp(`foo-XXXXXX'))dnl
 ifelse(len(defn(`file1')), len(defn(`file2')),
        `same length', `different')
@@ -8407,19 +8407,19 @@ $ @kbd{m4 -G}
 syscmd(`rm -f foo-*')sysval
 @result{}0
 define(`file1', maketemp(`foo-XXXXXX'))dnl
-@error{}m4:stdin:2: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:2: warning: maketemp: recommend using mkstemp instead
 define(`file2', maketemp(`foo-XXXXXX'))dnl
-@error{}m4:stdin:3: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:3: warning: maketemp: recommend using mkstemp instead
 ifelse(file1, file2, `same', `different file')
 @result{}same
 len(maketemp(`foo-XXXXX'))
-@error{}m4:stdin:5: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:5: warning: maketemp: recommend using mkstemp instead
 @result{}9
 define(`abc', `def')
 @result{}
 maketemp(`foo-abc')
 @result{}foo-def
-@error{}m4:stdin:7: Warning: maketemp: recommend using mkstemp instead
+@error{}m4:stdin:7: warning: maketemp: recommend using mkstemp instead
 syscmd(`test -f foo-*')sysval
 @result{}1
 @end example
@@ -8777,7 +8777,7 @@ twoline
 @result{}1
 @result{}2
 syncoutput(`blah')
-@error{}m4:stdin:18: Warning: syncoutput: unknown directive `blah'
+@error{}m4:stdin:18: warning: syncoutput: unknown directive `blah'
 @result{}
 @end example
 
@@ -9519,7 +9519,7 @@ forloop(`', `1', `2', ` odd iterator name')
 forloop(`i', `5 + 5', `0xc', ` 0x`'eval(i, `16')')
 @result{} 0xa 0xb 0xc
 forloop(`i', `a', `b', `non-numeric bounds')
-@error{}m4:stdin:6: Warning: eval: bad input: `(a) <= (b)'
+@error{}m4:stdin:6: warning: eval: bad input: `(a) <= (b)'
 @result{}
 @end example
 
@@ -10352,7 +10352,7 @@ m4wrap(`divnum(`demo of internal message')
 fatal_error(`inside wrapped text')')
 @result{}
 ^D
-@error{}m4:stdin:6: Warning: divnum: extra arguments ignored: 1 > 0
+@error{}m4:stdin:6: warning: divnum: extra arguments ignored: 1 > 0
 @result{}0
 @error{}m4:stdin:6: fatal error: inside wrapped text
 @end example
diff --git a/m4/output.c b/m4/output.c
index cbd37abe..72902f36 100644
--- a/m4/output.c
+++ b/m4/output.c
@@ -1098,7 +1098,7 @@ m4_freeze_diversions (m4 *context, FILE *file)
                   || file_stat.st_size != (unsigned long int) file_stat.st_size)
                 m4_error (context, EXIT_FAILURE, errno, NULL,
                           _("diversion too large"));
-              xfprintf (file, "D%d,%lu\n", diversion->divnum,
+              xfprintf (file, "%c%d,%lu\n", 'D', diversion->divnum,
                         (unsigned long int) file_stat.st_size);
             }
 
diff --git a/m4/utility.c b/m4/utility.c
index 337b8bb2..137f6fc2 100644
--- a/m4/utility.c
+++ b/m4/utility.c
@@ -167,7 +167,7 @@ const char *m4_info_name (const m4_call_info *caller)
    ARGS, on behalf of CALLER (if any), otherwise at the global
    position in CONTEXT.  If ERRNUM, decode the errno value as part of
    the message.  If STATUS, exit immediately with that status.  If
-   WARN, prepend 'Warning: '.  */
+   WARN, prepend 'warning: '.  */
 static void
 m4_verror_at_line (m4 *context, bool warn, int status, int errnum,
                    const m4_call_info *caller, const char *format,
@@ -206,9 +206,9 @@ m4_verror_at_line (m4 *context, bool warn, int status, int errnum,
      for non-memory reasons (unlikely), then still use the original
      format.  */
   if (warn && macro)
-    full = xasprintf (_("Warning: %s: %s"), macro, format);
+    full = xasprintf (_("warning: %s: %s"), macro, format);
   else if (warn)
-    full = xasprintf (_("Warning: %s"), format);
+    full = xasprintf (_("warning: %s"), format);
   else if (macro)
     full = xasprintf (_("%s: %s"), macro, format);
   verror_at_line (status, errnum, line ? file : NULL, line,
@@ -243,7 +243,7 @@ m4_error (m4 *context, int status, int errnum, const m4_call_info *caller,
 /* Issue a warning, if they are not being suppressed.  The message is
    printf-style, based on FORMAT and any other arguments, and the
    program name, location (if we are currently parsing an input file),
-   and "Warning:" are automatically prepended.  If ERRNUM is non-zero,
+   and "warning:" are automatically prepended.  If ERRNUM is non-zero,
    include strerror output in the message.  If CALLER, prepend the
    message with the macro where the message occurred.  If warnings are
    fatal, call exit immediately, otherwise exit status is
diff --git a/src/main.c b/src/main.c
index 1c7bfd84..e9f2599b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -390,7 +390,7 @@ main (int argc, char *const *argv, char *const *envp)
         case HASHSIZE_OPTION:
           /* -H was supported in 1.4.x, but is a no-op now.  FIXME -
              remove support for -H after 2.0.  */
-          error (0, 0, _("Warning: `%s' is deprecated"),
+          error (0, 0, _("warning: `%s' is deprecated"),
                  optchar == 'H' ? "-H" : "--hashsize");
           break;
 
@@ -399,13 +399,13 @@ main (int argc, char *const *argv, char *const *envp)
           /* Compatibility junk: options that other implementations
              support, but which we ignore as no-ops and don't list in
              --help.  */
-          error (0, 0, _("Warning: `-%c' is deprecated"),
+          error (0, 0, _("warning: `-%c' is deprecated"),
                  optchar);
           break;
 
         case WORD_REGEXP_OPTION:
           /* Supported in 1.4.x as -W, but no longer present.  */
-          error (0, 0, _("Warning: `%s' is deprecated"), "--word-regexp");
+          error (0, 0, _("warning: `%s' is deprecated"), "--word-regexp");
           break;
 
         case 's':
@@ -451,7 +451,7 @@ main (int argc, char *const *argv, char *const *envp)
               errno = 0;
               strtol (optarg, &end, 10);
               if (*end == '\0' && errno == 0)
-                error (0, 0, _("Warning: recommend using `-B ./%s' instead"),
+                error (0, 0, _("warning: recommend using `-B ./%s' instead"),
                        optarg);
             }
           /* fall through */
@@ -541,7 +541,7 @@ main (int argc, char *const *argv, char *const *envp)
           break;
 
         case 'e':
-          error (0, 0, _("Warning: `%s' is deprecated, use `%s' instead"),
+          error (0, 0, _("warning: `%s' is deprecated, use `%s' instead"),
                  "-e", "-i");
           /* fall through */
         case 'i':
@@ -553,7 +553,7 @@ main (int argc, char *const *argv, char *const *envp)
           break;
 
         case ARGLENGTH_OPTION:
-          error (0, 0, _("Warning: `%s' is deprecated, use `%s' instead"),
+          error (0, 0, _("warning: `%s' is deprecated, use `%s' instead"),
                  "--arglength", "--debuglen");
           /* fall through */
         case 'l':
@@ -579,7 +579,7 @@ main (int argc, char *const *argv, char *const *envp)
              stdout, and --error-output is misnamed since it does not
              affect error messages to stderr.  Change the meaning of -o
              after 2.1.  */
-          error (0, 0, _("Warning: `%s' is deprecated, use `%s' instead"),
+          error (0, 0, _("warning: `%s' is deprecated, use `%s' instead"),
                  optchar == 'o' ? "-o" : "--error-output", "--debugfile");
           /* Don't call m4_debug_set_output here, as it has side effects.  */
           debugfile = optarg;
diff --git a/tests/builtins.at b/tests/builtins.at
index 1993e6f4..aad46364 100644
--- a/tests/builtins.at
+++ b/tests/builtins.at
@@ -218,14 +218,14 @@ AT_CHECK_M4([define.m4], 0,
 [[new value.
 hello, world.
 base value.
-]], [[m4:define.m4:1: Warning: undefine: undefined macro `macro'
+]], [[m4:define.m4:1: warning: undefine: undefined macro `macro'
 ]])
 
 AT_CHECK_M4([--traditional define.m4], 0,
 [[new value.
 hello, world.
 base value.
-]], [[m4:define.m4:1: Warning: undefine: undefined macro `macro'
+]], [[m4:define.m4:1: warning: undefine: undefined macro `macro'
 ]])
 
 dnl check regression present 2008-02-22 to 2008-04-30.
@@ -728,7 +728,7 @@ AT_DATA([[in]],
 [[mkdtemp(`no_such_dir/m4-fooXXXXXX')
 ]])
 AT_CHECK_M4([in], [0], [[
-]], [[m4:in:1: Warning: mkdtemp: cannot create directory from template `no_such_dir/m4-fooXXXXXX': No such file or directory
+]], [[m4:in:1: warning: mkdtemp: cannot create directory from template `no_such_dir/m4-fooXXXXXX': No such file or directory
 ]])
 
 dnl Check that umask has an effect.  drws--S--T is okay.
@@ -757,7 +757,7 @@ AT_DATA([[in]],
 [[mkstemp(`no_such_dir/m4-fooXXXXXX')
 ]])
 AT_CHECK_M4([in], [0], [[
-]], [[m4:in:1: Warning: mkstemp: cannot create file from template `no_such_dir/m4-fooXXXXXX': No such file or directory
+]], [[m4:in:1: warning: mkstemp: cannot create file from template `no_such_dir/m4-fooXXXXXX': No such file or directory
 ]])
 
 dnl Check that extra X are appended, but not trailing NUL
diff --git a/tests/freeze.at b/tests/freeze.at
index 18d1c100..b75d5209 100644
--- a/tests/freeze.at
+++ b/tests/freeze.at
@@ -170,7 +170,7 @@ define 1
 my_define(bar, 4) 3
 bar${1}
 ]],
-[[m4:input.m4:5: Warning: popdef: undefined macro `my_define'
+[[m4:input.m4:5: warning: popdef: undefined macro `my_define'
 ]])
 
 dnl Test rejection of v2 features in a v1 frozen file
@@ -528,10 +528,10 @@ AT_CHECK_M4([-R frozen.m4f input.m4], 0,
 
 a
 ]],
-[[m4:input.m4:4: Warning: defn: a: builtin `b' requested by frozen file not found
-m4:input.m4:6: Warning: a: builtin `b' requested by frozen file not found
-m4:input.m4:8: Warning: a: builtin `b' requested by frozen file not found
-m4:input.m4:10: Warning: builtin: undefined builtin `b'
+[[m4:input.m4:4: warning: defn: a: builtin `b' requested by frozen file not found
+m4:input.m4:6: warning: a: builtin `b' requested by frozen file not found
+m4:input.m4:8: warning: a: builtin `b' requested by frozen file not found
+m4:input.m4:10: warning: builtin: undefined builtin `b'
 a:	<<b>>
 c:	`'
 ]], [], [ ])
diff --git a/tests/macros.at b/tests/macros.at
index 6b37cc14..31b44926 100644
--- a/tests/macros.at
+++ b/tests/macros.at
@@ -58,8 +58,8 @@ defun
 ]])
 
 AT_CHECK_M4([input.m4], 0, [expout],
-[[m4:input.m4:5: Warning: define: extra arguments ignored: 3 > 2
-m4:input.m4:10: Warning: defun: extra arguments ignored: 3 > 2
+[[m4:input.m4:5: warning: define: extra arguments ignored: 3 > 2
+m4:input.m4:10: warning: defun: extra arguments ignored: 3 > 2
 ]])
 
 AT_CLEANUP
@@ -94,7 +94,7 @@ AT_DATA([[expout]],
 ]])
 
 AT_CHECK_M4([--reload-state=frozen.m4f input.m4], 0, expout,
-[[m4:input.m4:4: Warning: defun: extra arguments ignored: 3 > 2
+[[m4:input.m4:4: warning: defun: extra arguments ignored: 3 > 2
 ]])
 
 AT_CLEANUP(freezeme.m4 frozen.m4f)
@@ -239,9 +239,9 @@ hej:	`def 4.'
 hej:	`def 3.'
 hej:	`def 2.'
 hej:	`def 1.'
-m4:pushpop.m4:18: Warning: dumpdef: undefined macro `hej'
-m4:pushpop.m4:20: Warning: dumpdef: undefined macro `mac2'
-m4:pushpop.m4:21: Warning: popdef: undefined macro `mac2'
+m4:pushpop.m4:18: warning: dumpdef: undefined macro `hej'
+m4:pushpop.m4:20: warning: dumpdef: undefined macro `mac2'
+m4:pushpop.m4:21: warning: popdef: undefined macro `mac2'
 ]])
 
 AT_CLEANUP
diff --git a/tests/modules.at b/tests/modules.at
index 1e9b2d95..3b082464 100644
--- a/tests/modules.at
+++ b/tests/modules.at
@@ -133,7 +133,7 @@ Dumpdef: .
 [[Test module loaded.
 test:	<test>
 Test module unloaded.
-m4:input.m4:6: Warning: dumpdef: undefined macro `test'
+m4:input.m4:6: warning: dumpdef: undefined macro `test'
 ]])
 
 AT_CLEANUP
@@ -455,10 +455,10 @@ modtest
 1
 1,2
 ]], [[Test module loaded.
-m4:input.m4:2: Warning: __test__: extra arguments ignored: 1 > 0
-m4:input.m4:3: Warning: __test__: extra arguments ignored: 2 > 0
-m4:input.m4:4: Warning: onearg: too few arguments: 0 < 1
-m4:input.m4:6: Warning: onearg: extra arguments ignored: 2 > 1
+m4:input.m4:2: warning: __test__: extra arguments ignored: 1 > 0
+m4:input.m4:3: warning: __test__: extra arguments ignored: 2 > 0
+m4:input.m4:4: warning: onearg: too few arguments: 0 < 1
+m4:input.m4:6: warning: onearg: extra arguments ignored: 2 > 1
 Test module unloaded.
 ]])
 
diff --git a/tests/null.err b/tests/null.err
index 38c610fe..2b0b3cf2 100644
--- a/tests/null.err
+++ b/tests/null.err
diff --git a/tests/options.at b/tests/options.at
index 82185e0b..80e70d7d 100644
--- a/tests/options.at
+++ b/tests/options.at
@@ -35,55 +35,55 @@ Try `m4 --help' for more information.
 
 dnl -H/--hashsize are no-ops since 2.0
 AT_CHECK_M4([-H1 --hashsize=1], [0], [],
-[[m4: Warning: `-H' is deprecated
-m4: Warning: `--hashsize' is deprecated
+[[m4: warning: `-H' is deprecated
+m4: warning: `--hashsize' is deprecated
 ]])
 
 dnl -S/-T are no-ops for compatibility
 AT_CHECK_M4([-S1 -T1], [0], [],
-[[m4: Warning: `-S' is deprecated
-m4: Warning: `-T' is deprecated
+[[m4: warning: `-S' is deprecated
+m4: warning: `-T' is deprecated
 ]])
 
 dnl -Bint can be confused with its no-op meaning in 1.4.x, but all other
 dnl uses of -B or its long option are okay
 AT_CHECK_M4([-B1], [0], [],
-[[m4: Warning: recommend using `-B ./1' instead
+[[m4: warning: recommend using `-B ./1' instead
 ]])
 AT_CHECK_M4([-B./1 --prepend-include=1], [0], [],
 [[]])
 
 dnl --error-output is a misleading name
 AT_CHECK_M4([--error-output=trace], [0], [],
-[[m4: Warning: `--error-output' is deprecated, use `--debugfile' instead
+[[m4: warning: `--error-output' is deprecated, use `--debugfile' instead
 ]])
 AT_CHECK([rm trace])
 
 dnl -o will change meaning in the future
 AT_CHECK_M4([-otrace], [0], [],
-[[m4: Warning: `-o' is deprecated, use `--debugfile' instead
+[[m4: warning: `-o' is deprecated, use `--debugfile' instead
 ]])
 AT_CHECK([rm trace])
 
 dnl -e is an odd spelling for --interactive
 AT_CHECK_M4([-e], [0], [],
-[[m4: Warning: `-e' is deprecated, use `-i' instead
+[[m4: warning: `-e' is deprecated, use `-i' instead
 ]])
 
 dnl --arglength is an older spelling for --debuglen
 AT_CHECK_M4([--arglength=10], [0], [],
-[[m4: Warning: `--arglength' is deprecated, use `--debuglen' instead
+[[m4: warning: `--arglength' is deprecated, use `--debuglen' instead
 ]])
 
 AT_CHECK_M4([--arglength=x], [1], [],
-[[m4: Warning: `--arglength' is deprecated, use `--debuglen' instead
+[[m4: warning: `--arglength' is deprecated, use `--debuglen' instead
 m4: invalid --arglength argument `x'
 ]])
 
 dnl --word-regexp from 1.4.x is no longer supported.  Can't test for its
 dnl alternate spelling -W, as that now means --warnings.
 AT_CHECK_M4([[--word-regexp='[a-zA-Z0-9_]+']], [0], [],
-[[m4: Warning: `--word-regexp' is deprecated
+[[m4: warning: `--word-regexp' is deprecated
 ]])
 
 AT_CLEANUP
@@ -214,16 +214,16 @@ AT_DATA([in], [[__line__
 dnl()
 ]])
 AT_CHECK_M4([in], [0], [[1
-]], [[m4:in:2: Warning: dnl: extra arguments ignored: 1 > 0
+]], [[m4:in:2: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 AT_CHECK_M4([in -g], [0], [[1
-]], [[m4:in:2: Warning: dnl: extra arguments ignored: 1 > 0
+]], [[m4:in:2: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 AT_CHECK_M4([in -G], [0], [[__line__
-]], [[m4:in:2: Warning: dnl: extra arguments ignored: 1 > 0
+]], [[m4:in:2: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 AT_CHECK_M4([in -W], [0], [[1
-]], [[m4:in:2: Warning: dnl: extra arguments ignored: 1 > 0
+]], [[m4:in:2: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 AT_CHECK_M4([in -Q], [0], [[1
 ]])
@@ -243,7 +243,7 @@ AT_CHECK_M4([in -g], [0], [[1
 AT_CHECK_M4([in -G], [0], [[__line__
 ]])
 AT_CHECK_M4([in -W], [0], [[__line__
-]], [[m4:in:2: Warning: dnl: extra arguments ignored: 1 > 0
+]], [[m4:in:2: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 AT_CHECK_M4([in -Q], [0], [[__line__
 ]])
@@ -528,21 +528,21 @@ dnl()
 
 dnl By default, warnings don't affect exit status
 AT_CHECK_M4([in], [0], [],
-[[m4:in:1: Warning: dnl: extra arguments ignored: 1 > 0
-m4:in:2: Warning: dnl: extra arguments ignored: 1 > 0
-m4:in:3: Warning: dnl: extra arguments ignored: 1 > 0
+[[m4:in:1: warning: dnl: extra arguments ignored: 1 > 0
+m4:in:2: warning: dnl: extra arguments ignored: 1 > 0
+m4:in:3: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 
 dnl With one -E, exit status changes, but execution continues
 AT_CHECK_M4([-E in], [1], [],
-[[m4:in:1: Warning: dnl: extra arguments ignored: 1 > 0
-m4:in:2: Warning: dnl: extra arguments ignored: 1 > 0
-m4:in:3: Warning: dnl: extra arguments ignored: 1 > 0
+[[m4:in:1: warning: dnl: extra arguments ignored: 1 > 0
+m4:in:2: warning: dnl: extra arguments ignored: 1 > 0
+m4:in:3: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 
 dnl With two -E, execution halts immediately
 AT_CHECK_M4([--fatal-warnings --fatal-warnings in], [1], [],
-[[m4:in:1: Warning: dnl: extra arguments ignored: 1 > 0
+[[m4:in:1: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 
 dnl Exit status can't be affected if there were no warnings
@@ -730,7 +730,7 @@ AT_CHECK_M4([--regexp-syntax= in], [0], [[0
 ]])
 
 AT_CHECK_M4([-rEXTENDED in], [0], [[
-]], [[m4:in:1: Warning: regexp: bad regular expression `(': Unmatched ( or \(
+]], [[m4:in:1: warning: regexp: bad regular expression `(': Unmatched ( or \(
 ]])
 
 AT_CHECK_M4([-rgnu-m4 in], [0], [[0
@@ -742,7 +742,7 @@ AT_CHECK_M4([-r"gnu M4" in], [0], [[0
 dnl Test behavior of -r intermixed with files
 AT_CHECK_M4([-rEXTENDED in --regexp-syntax in], [0], [[
 0
-]], [[m4:in:1: Warning: regexp: bad regular expression `(': Unmatched ( or \(
+]], [[m4:in:1: warning: regexp: bad regular expression `(': Unmatched ( or \(
 ]])
 
 AT_CLEANUP
@@ -821,7 +821,7 @@ hi
 dnl test parse error
 AT_CHECK_M4([--syncoutput=huh in], [0],
 [[hi
-]], [[m4: Warning: --syncoutput: unknown directive `huh'
+]], [[m4: warning: --syncoutput: unknown directive `huh'
 ]])
 
 AT_CLEANUP
diff --git a/tests/others.at b/tests/others.at
index a5d05e16..32589570 100644
--- a/tests/others.at
+++ b/tests/others.at
@@ -437,7 +437,7 @@ AT_CHECK_M4(["$abs_srcdir/null.m4"], [1],
 [[# This file tests m4 behavior on NUL bytes.
 ]], [stderr])
 AT_CHECK([sed "s|$abs_srcdir/||" stderr], [0],
-[[m4:null.m4:5: Warning: m4exit: non-numeric argument `2\0002'
+[[m4:null.m4:5: warning: m4exit: non-numeric argument `2\0002'
 ]])
 
 AT_CLEANUP
@@ -706,7 +706,7 @@ AT_DATA([in.m4], [[dnl(
 AT_CHECK([($M4 -EE; cat) < in.m4], [0], [[trailing data
 ]], [stderr])
 AT_CHECK([[$SED 's/^[^:]*[lt-]*m4[.ex]*:/m4:/' stderr]], [0],
-[[m4:stdin:1: Warning: dnl: extra arguments ignored: 1 > 0
+[[m4:stdin:1: warning: dnl: extra arguments ignored: 1 > 0
 ]])
 
 dnl Not all sed and libc combinations get the remaining tests right (for