Configure patches -01 and -02 for 5.004_61.

p4raw-id: //depot/perl@783

1 files changed, 187 insertions, 13 deletions

diff --git a/hints/README.hints b/hints/README.hints
index 2c27068e38..e36bd6d1dd 100644
--- a/hints/README.hints
+++ b/hints/README.hints
@@ -1,17 +1,24 @@
+=head1 NAME
+
+README.hints
+
+=head1 DESCRIPTION
+
 These files are used by Configure to set things which Configure either
 can't or doesn't guess properly.  Most of these hint files have been
 tested with at least some version of perl5, but some are still left
-over from perl4.  I would appreciate hearing about any problems
-or suggested changes.
+over from perl4.
+
+Please send any problems or suggested changes to perlbug@perl.com.
 
 Hint file naming convention:   Each hint file name should have only
-one '.'.  (This is for portability to non-unix filesystems.)  Names
+one '.'.  (This is for portability to non-unix file systems.)  Names
 should also fit in <= 14 characters, for portability to older SVR3
 systems.  File names are of the form $osname_$osvers.sh, with all '.'
-changed to '_', and all characters such as '/' that don't belong in
+changed to '_', and all characters (such as '/') that don't belong in
 Unix filenames omitted.
 
-For example, consider SunOS 4.1.3.  Configure determines $osname=sunos
+For example, consider Sun OS 4.1.3.  Configure determines $osname=sunos
 (all names are converted to lower case) and $osvers=4.1.3.  Configure
 will search for an appropriate hint file in the following order:
 
@@ -22,18 +29,185 @@ will search for an appropriate hint file in the following order:
 
 If you need to create a hint file, please try to use as general a name
 as possible and include minor version differences inside case or test
-statements.  Be sure also to include a default choice.  (See
-aix.sh for one example.) That way, if you write a hint file for
-foonix 3.2, it might still work without any changes when foonix 3.3 is
-released.
+statements.  For example, for IRIX 6.X, we have the following hints
+files:
+
+	irix_6_0.sh
+	irix_6_1.sh
+	irix_6.sh
+
+That is, 6.0 and 6.1 have their own special hints, but 6.2, 6.3, and
+up are all handled by the same irix_6.sh.  That way, we don't have to
+make a new hint file every time the IRIX O/S is upgraded.
+
+If you need to test for specific minor version differences in your
+hints file, be sure to include a default choice.  (See aix.sh for one
+example.) That way, if you write a hint file for foonix 3.2, it might
+still work without any changes when foonix 3.3 is released.
 
 Please also comment carefully on why the different hints are needed.
 That way, a future version of Configure may be able to automatically
-detect what is needed.  A glossary of config.sh variables is in the
-file Porting/Glossary.
+detect what is needed.
+
+A glossary of config.sh variables is in the file Porting/Glossary.
+
+=head1 Hint file tricks
+
+=head2 Printing critical messages
+
+[This is still experimental]
+
+If you have a *REALLY* important message that the user ought to see at
+the end of the Configure run, you can store it in the file
+'config.msg'.  At the end of the Configure run, Configure will display
+the contents of this file.  Currently, the only place this is used is
+in Configure itself to warn about the need to set LD_LIBRARY_PATH if
+you are building a shared libperl.so.
+
+To use this feature, just do something like the following
+
+	$cat <<EOM  | $tee -a ../config.msg >&4
+
+    This is a really important message.  Be sure to read it
+    before you type 'make'.
+    EOM
+
+This message will appear on the screen as the hint file is being
+processed and again at the end of Configure.
+
+Please use this sparingly.
+
+=head2 Propagating variables to config.sh
+
+Sometimes, you want an extra variable to appear in config.sh.  For
+example, if your system can't compile toke.c with the optimizer on,
+you can put
+
+    toke_cflags='optimize=""'
+
+at the beginning of a line in your hints file.  Configure will then
+extract that variable and place it in your config.sh file.  Later,
+while compiling toke.c, the cflags shell script will eval $toke_cflags
+and hence compile toke.c without optimization.
+
+Note that for this to work, the variable you want to propagate must
+appear in the first column of the hint file.  It is extracted by
+Configure with a simple sed script, so beware that surrounding case
+statements aren't any help.
+
+By contrast, if you don't want Configure to propagate your temporary
+variable, simply indent it by a leading tab in your hint file.
+
+For example, prior to 5.002, a bug in scope.c led to perl crashing
+when compiled with -O in AIX 4.1.1.  The following "obvious"
+workaround in hints/aix.sh wouldn't work as expected:
+
+    case "$osvers" in
+	4.1.1)
+    scope_cflags='optimize=""'
+	;;
+    esac
+
+because Configure doesn't parse the surrounding 'case' statement, it
+just blindly propagates any variable that starts in the first column.
+For this particular case, that's probably harmless anyway.
+
+Three possible fixes are:
+
+=over
+
+=item 1
+
+Create an aix_4_1_1.sh hint file that contains the scope_cflags
+line and then sources the regular aix hints file for the rest of
+the information.
+
+=item 2
+
+Do the following trick:
+
+    scope_cflags='case "$osvers" in 4.1*) optimize=" ";; esac'
+
+Now when $scope_cflags is eval'd by the cflags shell script, the
+case statement is executed.  Of course writing scripts to be eval'd is
+tricky, especially if there is complex quoting.  Or,
+
+=item 3
+
+Write directly to Configure's temporary file UU/config.sh.
+You can do this with
+
+    case "$osvers" in
+	4.1.1)
+	echo "scope_cflags='optimize=\"\"'" >> UU/config.sh
+	scope_cflags='optimize=""'
+	;;
+    esac
+
+Note you have to both write the definition to the temporary
+UU/config.sh file and set the variable to the appropriate value.
+
+This is sneaky, but it works.  Still, if you need anything this
+complex, perhaps you should create the separate hint file for
+aix 4.1.1.
+
+=back
+
+=head2 Call-backs
+
+=over 4
+
+=item Warning
+
+All of the following is experimental and subject to change.  But it
+probably won't change much. :-)
+
+=item Compiler-related flags
+
+The settings of some things, such as optimization flags, may depend on
+the particular compiler used.  For example, for ISC we have the
+following:
+
+    case "$cc" in
+    *gcc*)  ccflags="$ccflags -posix"
+	    ldflags="$ldflags -posix"
+	    ;;
+    *)      ccflags="$ccflags -Xp -D_POSIX_SOURCE"
+	    ldflags="$ldflags -Xp"
+	    ;;
+    esac
+
+However, the hints file is processed before the user is asked which
+compiler should be used.  Thus in order for these hints to be useful,
+the user must specify  sh Configure -Dcc=gcc on the command line, as
+advised by the INSTALL file.
+
+For versions of perl later than 5.004_61, this problem can
+be circumvented by the use of "call-back units".  That is, the hints
+file can tuck this information away into a file UU/cc.cbu.  Then,
+after Configure prompts the user for the C compiler, it will load in
+and run the UU/cc.cbu "call-back" unit.  See hints/solaris_2.sh for an
+example.
+
+=item Threading-related flags
+
+Similarly, after Configure prompts the user about whether or not to
+compile Perl with threads, it will look for a "call-back" unit
+usethreads.cbu.  See hints/linux.sh for an example.
+
+=item Future status
+
+I hope this "call-back" scheme is simple enough to use but powerful
+enough to deal with most situations.  Still, there are certainly cases
+where it's not enough.  For example, for aix we actually change
+compilers if we are using threads.
+
+I'd appreciate feedback on whether this is sufficiently general to be
+helpful, or whether we ought to simply continue to require folks to
+say things like "sh Configure -Dcc=gcc -Dusethreads" on the command line.
+
+=back
 
 Have the appropriate amount of fun :-)
 
     Andy Dougherty		doughera@lafcol.lafayette.edu
-    Dept. of Physics
-    Lafayette College, Easton PA 18042