[PATCH v3] 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.

---
v3: Git mishap did not squash together both changes.  Restore the
    removal of the $(PERL) conditional.

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

diff --git a/malloc/Makefile b/malloc/Makefile
index cc14cf66c9..02aff1bd1d 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -250,7 +250,6 @@ others-extras = mcheck-init.o
 aux := set-freeres thread-freeres
 
 # The Perl script to analyze the output of the mtrace functions.
-ifneq ($(PERL),no)
 install-bin-script = mtrace
 generated += mtrace
 
@@ -261,7 +260,6 @@ address-width=10
 else
 address-width=18
 endif
-endif
 
 # Unless we get a test for the availability of libgd which also works
 # for cross-compiling we disable the memusagestat generation in this
@@ -349,7 +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: 4f1cf0c0e1764bd77235b07ff63631e866939ec6