Make etags path used by build system configurable

This commit allows users to specify a path to their "etags"
executable for use when doing "make tags".
I based this patch off of this one from upstream automake:
https://git.savannah.gnu.org/cgit/automake.git/commit/m4?id=d2ccbd7eb38d6a4277d6f42b994eb5a29b1edf29
This means that I just supplied variables that the user can override
for the tags programs, rather than having the configure scripts
actually check for them. I handle etags and ctags separately because
the intl subdirectory has separate targets for them. This commit
only affects the subdirectories that use handwritten Makefiles; the
ones that use automake will have to wait until we update the version
of automake used to be 1.16.4 or newer before they'll be fixed.

Addresses #103021

gcc/ChangeLog:

	PR other/103021
	* Makefile.in: Substitute CTAGS, ETAGS, and CSCOPE
	variables. Use ETAGS variable in TAGS target.
	* configure: Regenerate.
	* configure.ac: Allow CTAGS, ETAGS, and CSCOPE
	variables to be overridden.

gcc/ada/ChangeLog:

	PR other/103021
	* gcc-interface/Make-lang.in: Use ETAGS variable in
	TAGS target.

gcc/c/ChangeLog:

	PR other/103021
	* Make-lang.in: Use ETAGS variable in TAGS target.

gcc/cp/ChangeLog:

	PR other/103021
	* Make-lang.in: Use ETAGS variable in TAGS target.

gcc/d/ChangeLog:

	PR other/103021
	* Make-lang.in: Use ETAGS variable in TAGS target.

gcc/fortran/ChangeLog:

	PR other/103021
	* Make-lang.in: Use ETAGS variable in TAGS target.

gcc/go/ChangeLog:

	PR other/103021
	* Make-lang.in: Use ETAGS variable in TAGS target.

gcc/objc/ChangeLog:

	PR other/103021
	* Make-lang.in: Use ETAGS variable in TAGS target.

gcc/objcp/ChangeLog:

	PR other/103021
	* Make-lang.in: Use ETAGS variable in TAGS target.

intl/ChangeLog:

	PR other/103021
	* Makefile.in: Use ETAGS variable in TAGS target,
	CTAGS variable in CTAGS target, and MKID variable
	in ID target.
	* configure: Regenerate.
	* configure.ac: Allow CTAGS, ETAGS, and MKID
	variables to be overridden.

libcpp/ChangeLog:

	PR other/103021
	* Makefile.in: Use ETAGS variable in TAGS target.
	* configure: Regenerate.
	* configure.ac: Allow ETAGS variable to be overridden.

libiberty/ChangeLog:

	PR other/103021
	* Makefile.in: Use ETAGS variable in TAGS target.
	* configure: Regenerate.
	* configure.ac: Allow ETAGS variable to be overridden.

3 files changed, 14 insertions, 1 deletions

diff --git a/libiberty/Makefile.in b/libiberty/Makefile.in
index 884cc6c4af2..0d41a79cc98 100644
--- a/libiberty/Makefile.in
+++ b/libiberty/Makefile.in
@@ -429,8 +429,10 @@ stamp-noasandir:
 
 .PHONY: all etags tags TAGS ls clean stage1 stage2
 
+ETAGS = @ETAGS@
+
 etags tags TAGS: etags-subdir
-	cd $(srcdir) && etags $(CFILES)
+	cd $(srcdir) && $(ETAGS) $(CFILES)
 
 # The standalone demangler (c++filt) has been moved to binutils.
 # But make this target work anyway for demangler hacking.
diff --git a/libiberty/configure b/libiberty/configure
index 3c7e588b16b..0a797255c70 100755
--- a/libiberty/configure
+++ b/libiberty/configure
@@ -659,6 +659,7 @@ HAVE_PERL
 PERL
 BUILD_INFO
 MAKEINFO
+ETAGS
 NOTMAINT
 MAINT
 libiberty_topdir
@@ -2558,6 +2559,11 @@ else
   NOTMAINT=''
 fi
 
+if test -z "$ETAGS"; then
+  ETAGS=etags
+fi
+
+
 # Do we have a single-tree copy of texinfo?  Even if we do, we can't
 # rely on it - libiberty is built before texinfo.
 # Extract the first word of "makeinfo", so it can be a program name with args.
diff --git a/libiberty/configure.ac b/libiberty/configure.ac
index 4b78c1830c7..84a7b378fad 100644
--- a/libiberty/configure.ac
+++ b/libiberty/configure.ac
@@ -61,6 +61,11 @@ fi
 AC_SUBST(MAINT)dnl
 AC_SUBST(NOTMAINT)dnl
 
+if test -z "$ETAGS"; then
+  ETAGS=etags
+fi
+AC_SUBST([ETAGS])
+
 # Do we have a single-tree copy of texinfo?  Even if we do, we can't
 # rely on it - libiberty is built before texinfo.
 AC_CHECK_PROG(MAKEINFO, makeinfo, makeinfo, )