[PATCH v2] malloc: Always install mtrace (bug 31892)

[Florian Weimer <fweimer@redhat.com>]

Generation of the Perl script does not depend on Perl, so we can
always install it even if $(PERL) is not set during the build.

Change the malloc/mtrace.pl text substition not to rely on $(PERL).
Instead use PATH at run time to find the Perl interpreter. The Perl
interpreter cannot execute directly a script that starts with
“#! /bin/sh”: it always executes it with /bin/sh.  There is no
perl command line switch to disable this behavior.  Instead, use
the Perl require function to execute the script.  The additional
shift calls remove the “.” shell arguments.  Perl interprets the
“.” as a string concatenation operator, making the expression
syntactically valid.

Tested on x86_64-linux-gnu with Perl installed.

---
 malloc/Makefile  | 2 +-
 malloc/mtrace.pl | 7 +++----
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/malloc/Makefile b/malloc/Makefile
index c7d6678a40..02aff1bd1d 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -347,7 +347,7 @@ sLIBdir := $(shell echo $(slibdir) | sed 's,lib\(\|64\)$$,\\\\$$LIB,')
 
 $(objpfx)mtrace: mtrace.pl
 	rm -f $@.new
-	sed -e 's|@PERL@|$(PERL)|' -e 's|@XXX@|$(address-width)|' \
+	sed -e 's|@XXX@|$(address-width)|' \
 	    -e 's|@VERSION@|$(version)|' \
 	    -e 's|@PKGVERSION@|$(PKGVERSION)|' \
 	    -e 's|@REPORT_BUGS_TO@|$(REPORT_BUGS_TO)|' $^ > $@.new \
diff --git a/malloc/mtrace.pl b/malloc/mtrace.pl
index 075da0d9f1..dc6085820e 100644
--- a/malloc/mtrace.pl
+++ b/malloc/mtrace.pl
@@ -1,6 +1,6 @@
-#! @PERL@
-eval "exec @PERL@ -S $0 $@"
-    if 0;
+#! /bin/sh
+eval exec "perl -e 'shift; \$progname=shift; shift; require \$progname'" . "$0" . "$@"
+   if 0;
 # Copyright (C) 1997-2024 Free Software Foundation, Inc.
 # This file is part of the GNU C Library.
 # Based on the mtrace.awk script.
@@ -22,7 +22,6 @@ eval "exec @PERL@ -S $0 $@"
 $VERSION = "@VERSION@";
 $PKGVERSION = "@PKGVERSION@";
 $REPORT_BUGS_TO = '@REPORT_BUGS_TO@';
-$progname = $0;
 
 sub usage {
     print "Usage: mtrace [OPTION]... [Binary] MtraceData\n";

base-commit: 8919429b7553aaee0df74947fee7e0649923674b