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/libcpp/Makefile.in b/libcpp/Makefile.in
index 34e4206..6b6554b 100644
--- a/libcpp/Makefile.in
+++ b/libcpp/Makefile.in
@@ -264,11 +264,13 @@ po/$(PACKAGE).pot: $(libcpp_a_SOURCES)
 	sed 's:$(srcdir)/::g' <po/$(PACKAGE).pot.tmp >po/$(PACKAGE).pot
 	rm po/$(PACKAGE).pot.tmp
 
+ETAGS = @ETAGS@
+
 TAGS_SOURCES = $(libcpp_a_SOURCES) internal.h system.h ucnid.h \
     include/cpplib.h include/line-map.h include/mkdeps.h include/symtab.h
 
 TAGS: $(TAGS_SOURCES)
-	cd $(srcdir) && etags $(TAGS_SOURCES)
+	cd $(srcdir) && $(ETAGS) $(TAGS_SOURCES)
 
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.
diff --git a/libcpp/configure b/libcpp/configure
index 9674cd9..2797292 100755
--- a/libcpp/configure
+++ b/libcpp/configure
@@ -652,6 +652,7 @@ noexception_flags
 WARN_PEDANTIC
 c_warn
 warn
+ETAGS
 AUTOHEADER
 AUTOCONF
 ACLOCAL
@@ -4896,6 +4897,11 @@ done
 test -n "$AUTOHEADER" || AUTOHEADER="$MISSING autoheader"
 
 
+if test -z "$ETAGS"; then
+  ETAGS=etags
+fi
+
+
 # Figure out what compiler warnings we can enable.
 # See config/warnings.m4 for details.
 
diff --git a/libcpp/configure.ac b/libcpp/configure.ac
index 1efa96f..bc2373c 100644
--- a/libcpp/configure.ac
+++ b/libcpp/configure.ac
@@ -22,6 +22,11 @@ AC_CHECK_PROGS([ACLOCAL], [aclocal], [$MISSING aclocal])
 AC_CHECK_PROGS([AUTOCONF], [autoconf], [$MISSING autoconf])
 AC_CHECK_PROGS([AUTOHEADER], [autoheader], [$MISSING autoheader])
 
+if test -z "$ETAGS"; then
+  ETAGS=etags
+fi
+AC_SUBST([ETAGS])
+
 # Figure out what compiler warnings we can enable.
 # See config/warnings.m4 for details.