>From f4ba49a2f68d6640711b7de41390acb7a187ff0c Mon Sep 17 00:00:00 2001
From: Nikolai Merinov <nikolai.merinov@member.fsf.org>
Date: Thu, 7 Mar 2019 22:33:13 +0500
Subject: [PATCH] _AC_DO _AC_DO_STDERR: Evaluate argument twice

The `AC_COMPILE_IFELSE', `AC_LINK_IFELSE', `AC_PREPROC_IFELSE' macros
use the `_AC_DO_STDERR` macro in the following manner:

> ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
> _AC_DO_STDERR($ac_compile) # Unescape variable only once

Full compilation process works like the following:

> CFLAGS='-DFLAG=\"quoted string\"' ./configure
> # Produce Makefile with CFLAGS = -DFLAG=\"quoted string\"
> make # substitute args in "$(CC) $(CFLAGS) ..." recipe and call shell
> gcc -DFLAG="quoted string" ... # Arg was evaluated twice

In order to have same behavior during a configuration stage and during
a compilation stage we should evaluate a passed argument twice in
_AC_DO_STDERR command: in second time we'll be able to unquote strings
in user-supplied variables as it happens during make rules execution.

The `_AC_DO' macro used through the `_AC_DO_VAR' macro in similar
manner in many places and should work by same rules.

* lib/autoconf/general.m4 (_AC_DO_STDERR): Reuse `_AC_DO_ECHO' trick
to evaluate arguments twice if compile string have no '\"', '`', or
'\\' symbols.
  (_AC_DO): Same changes.
* tests/compile.at: Add test for CPPFLAGS with escaped string in
  autoconf compilation commands and with compilation through Makefile.
---
 NEWS                    |  6 +++
 lib/autoconf/general.m4 | 22 ++++++++--
 tests/compile.at        | 92 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index dbbea222..b637b2e3 100644
--- a/NEWS
+++ b/NEWS
@@ -229,6 +229,12 @@ GNU Autoconf NEWS - User visible changes.
   subdirectory.  See the documentation of AC_OPENMP for further
   explanation.
 
+*** The _AC_DO_STDERR and _AC_DO macros now evaluate a COMMAND argument twice.
+
+  This change consolidate behavior for user-supplied arguments
+  between the AC_COMPILE_IFELSE and AC_LINK_IFELSE macros and
+  compilation commands used in makefiles.
+
 ** New features
 
 *** Configure scripts now support a ‘--runstatedir’ option.
diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index 16f0d074..1fecffdb 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -2607,16 +2607,30 @@ AS_ECHO(["$ac_try_echo"])])
 # Eval COMMAND, save the exit status in ac_status, and log it.
 # For internal use only.
 AC_DEFUN([_AC_DO],
-[_AC_RUN_LOG([eval "$1"],
-	     [_AC_DO_ECHO([$1])])])
+[m4_if([$1], [$ac_do], [], [ac_do="$1"
+])]dnl
+[[case "(($ac_do" in
+  *\"* | *\`* | *\\*) ac_do_command=\$ac_do;;
+  *) ac_do_command=$ac_do;;
+esac
+eval ac_do_command="\"$ac_do_command\""]
+_AC_RUN_LOG([eval "$ac_do_command"],
+		   [_AC_DO_ECHO([$ac_do])])])
 
 
 # _AC_DO_STDERR(COMMAND)
 # ----------------------
 # Like _AC_RUN_LOG_STDERR, but eval (instead of running) COMMAND.
 AC_DEFUN([_AC_DO_STDERR],
-[_AC_RUN_LOG_STDERR([eval "$1"],
-		    [_AC_DO_ECHO([$1])])])
+[m4_if([$1], [$ac_do_stderr], [], [ac_do_stderr="$1"
+])]dnl
+[[case "(($ac_do_stderr" in
+  *\"* | *\`* | *\\*) ac_do_stderr_command=\$ac_do_stderr;;
+  *) ac_do_stderr_command=$ac_do_stderr;;
+esac
+eval ac_do_stderr_command="\"$ac_do_stderr_command\""]
+_AC_RUN_LOG_STDERR([eval "$ac_do_stderr_command"],
+		   [_AC_DO_ECHO([$ac_do_stderr])])])
 
 
 # _AC_DO_VAR(VARIABLE)
diff --git a/tests/compile.at b/tests/compile.at
index 4847f111..ae116a23 100644
--- a/tests/compile.at
+++ b/tests/compile.at
@@ -344,6 +344,98 @@ AT_CHECK_CONFIGURE([-q])
 
 AT_CLEANUP
 
+## -------------------------- ##
+## Quoted string in CPPFLAGS  ##
+## -------------------------- ##
+
+AT_SETUP([Qouted string in CPPFLAGS])
+
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_PROG_CC
+CPPFLAGS='-DSTRING=\"Hello,\ World\"'
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[const char hw[] = STRING;]], [return 0])],
+	      [],
+	      [AC_MSG_ERROR([compiling program with quoted CFLAGS failed])])
+AC_OUTPUT
+]])
+
+AT_CHECK_AUTOCONF
+AT_CHECK_CONFIGURE
+
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_PROG_CC
+CPPFLAGS='-DSTRING=\"Hello,\ World\"'
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
+]])
+
+AT_DATA([Makefile.in],
+[[foo@EXEEXT@: foo.@OBJEXT@
+	@CC@ @CFLAGS@ @LDFLAGS@ -o $@ foo.@OBJEXT@
+
+foo.@OBJEXT@: foo.c
+	@CC@ @CPPFLAGS@ @CFLAGS@ -c foo.c
+]])
+
+AT_DATA([foo.c],
+[[const char hw[] = STRING;
+int main (void)
+{
+  return 0;
+}
+]])
+
+AT_CHECK_AUTOCONF
+AT_CHECK_CONFIGURE
+AT_CHECK_MAKE
+
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_PROG_CC
+CPPFLAGS='-DRETURN="exit(0)"'
+AC_RUN_IFELSE([AC_LANG_PROGRAM([@%:@include <stdlib.h>], [RETURN; return 1])],
+	      [],
+	      [AC_MSG_ERROR([Running program with parenthesis in macro failed])])
+AC_OUTPUT
+]])
+
+AT_CHECK_AUTOCONF
+AT_CHECK_CONFIGURE
+
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_PROG_CC
+CPPFLAGS='-DRETURN="exit(0)"'
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
+]])
+
+AT_DATA([Makefile.in],
+[[foo@EXEEXT@: foo.@OBJEXT@
+	@CC@ @CFLAGS@ @LDFLAGS@ -o $@ foo.@OBJEXT@
+
+foo.@OBJEXT@: foo.c
+	@CC@ @CPPFLAGS@ @CFLAGS@ -c foo.c
+]])
+
+AT_DATA([foo.c],
+[[#include <stdlib.h>
+int main (void)
+{
+  RETURN;
+  return 1;
+}
+]])
+
+AT_CHECK_AUTOCONF
+AT_CHECK_CONFIGURE
+AT_CHECK_MAKE
+AT_CHECK([./foo])
+
+AT_CLEANUP
+
 ## --------------------------  ##
 ## Order of `rm' and actions.  ##
 ## --------------------------  ##
-- 
2.29.2