[PATCH util-macros 3/3] XORG_LD_WRAP: check if linker supports -wrap

[Gaetan Nadon]

Used mainly by test cases using a wrapper function.

Signed-off-by: Gaetan Nadon <memsize at videotron.ca>
---
 Makefile.am              |    1 +
 ax_check_linker_flags.m4 |   77 ++++++++++++++++++++++++++++++++++++++++++++++
 xorg-macros.m4.in        |   22 +++++++++++++
 3 files changed, 100 insertions(+), 0 deletions(-)
 create mode 100644 ax_check_linker_flags.m4

diff --git a/Makefile.am b/Makefile.am
index 134a5cc..14e89af 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -21,6 +21,7 @@
 
 aclocaldir = $(datadir)/aclocal
 aclocal_DATA = xorg-macros.m4
+dist_aclocal_DATA = ax_check_linker_flags.m4
 dist_pkgdata_DATA = INSTALL
 
 # Previous versions used to install xorgversion.m4, now integrated
diff --git a/ax_check_linker_flags.m4 b/ax_check_linker_flags.m4
new file mode 100644
index 0000000..894713c
--- /dev/null
+++ b/ax_check_linker_flags.m4
@@ -0,0 +1,77 @@
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_check_linker_flags.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_LINKER_FLAGS(FLAGS, [ACTION-SUCCESS], [ACTION-FAILURE])
+#
+# DESCRIPTION
+#
+#   Check whether the given linker FLAGS work with the current language's
+#   linker, or whether they give an error.
+#
+#   ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on
+#   success/failure.
+#
+#   NOTE: Based on AX_CHECK_COMPILER_FLAGS.
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Mike Frysinger <vapier at gentoo.org>
+#   Copyright (c) 2009 Steven G. Johnson <stevenj at alum.mit.edu>
+#   Copyright (c) 2009 Matteo Frigo
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 6
+
+AC_DEFUN([AX_CHECK_LINKER_FLAGS],
+[AC_MSG_CHECKING([whether the linker accepts $1])
+dnl Some hackery here since AC_CACHE_VAL can't handle a non-literal varname:
+AS_LITERAL_IF([$1],
+  [AC_CACHE_VAL(AS_TR_SH(ax_cv_linker_flags_[$1]), [
+      ax_save_FLAGS=$LDFLAGS
+      LDFLAGS="$1"
+      AC_LINK_IFELSE([AC_LANG_PROGRAM()],
+        AS_TR_SH(ax_cv_linker_flags_[$1])=yes,
+        AS_TR_SH(ax_cv_linker_flags_[$1])=no)
+      LDFLAGS=$ax_save_FLAGS])],
+  [ax_save_FLAGS=$LDFLAGS
+   LDFLAGS="$1"
+   AC_LINK_IFELSE([AC_LANG_PROGRAM()],
+     eval AS_TR_SH(ax_cv_linker_flags_[$1])=yes,
+     eval AS_TR_SH(ax_cv_linker_flags_[$1])=no)
+   LDFLAGS=$ax_save_FLAGS])
+eval ax_check_linker_flags=$AS_TR_SH(ax_cv_linker_flags_[$1])
+AC_MSG_RESULT($ax_check_linker_flags)
+if test "x$ax_check_linker_flags" = xyes; then
+	m4_default([$2], :)
+else
+	m4_default([$3], :)
+fi
+])dnl AX_CHECK_LINKER_FLAGS
diff --git a/xorg-macros.m4.in b/xorg-macros.m4.in
index c9ca311..6191680 100644
--- a/xorg-macros.m4.in
+++ b/xorg-macros.m4.in
@@ -973,6 +973,7 @@ AC_MSG_RESULT([$build_specs])
 #
 AC_DEFUN([XORG_ENABLE_UNIT_TESTS],[
 AC_BEFORE([$0], [XORG_WITH_GLIB])
+AC_BEFORE([$0], [XORG_LD_WRAP])
 m4_define([_defopt], m4_default([$1], [auto]))
 AC_ARG_ENABLE(unit-tests, AS_HELP_STRING([--enable-unit-tests],
 	[Enable building unit test cases (default: ]_defopt[)]),
@@ -1036,6 +1037,27 @@ fi
 AM_CONDITIONAL([HAVE_GLIB], [test "$have_glib" = yes])
 ]) # XORG_WITH_GLIB
 
+# XORG_LD_WRAP
+# ------------
+# Minimum version: 1.13.0
+#
+# Check if linker supports -wrap, passed via compiler flags
+#
+# When used with ENABLE_UNIT_TESTS, it is assumed -wrap is used for unit testing.
+# Otherwise the value of $enable_unit_tests is blank.
+#
+AC_DEFUN([XORG_LD_WRAP],[
+AX_CHECK_LINKER_FLAGS([-Wl,-wrap,exit],[have_ld_wrap=yes],[have_ld_wrap=no])
+# Not having ld wrap when unit testing has been explicitly requested is an error
+if test "x$enable_unit_tests" = x"yes"; then
+  if test "x$have_ld_wrap" = x"no"; then
+    AC_MSG_ERROR([--enable-unit-tests=yes specified but ld -wrap support is not available])
+  fi
+fi
+AM_CONDITIONAL([HAVE_LD_WRAP], [test "$have_ld_wrap" = yes])
+#
+]) # XORG_LD_WRAP
+
 # XORG_CHECK_MALLOC_ZERO
 # ----------------------
 # Minimum version: 1.0.0
-- 
1.6.0.4