[vte] build: m4: Update from upstream

[Christian Persch <chpe src gnome org>]

commit d7d095c0db1d14243d278603c9a389ff77148c6d
Author: Christian Persch <chpe gnome org>
Date:   Tue Mar 31 19:52:22 2015 +0200

    build: m4: Update from upstream
    
    Update with latest version from systemd.

 acinclude.m4 |   31 ++++++++++++++++---------------
 1 files changed, 16 insertions(+), 15 deletions(-)
---
diff --git a/acinclude.m4 b/acinclude.m4
index 211f9a3..97f094b 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -34,18 +34,19 @@ dnl this special exception to the GPL to apply to your modified version as
 dnl well.
 
 dnl Check if FLAG in ENV-VAR is supported by compiler and append it
-dnl to WHERE-TO-APPEND variable
+dnl to WHERE-TO-APPEND variable. Note that we invert -Wno-* checks to
+dnl -W* as gcc cannot test for negated warnings.
 dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])
 
 AC_DEFUN([CC_CHECK_FLAG_APPEND], [
   AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2],
                  AS_TR_SH([cc_cv_$2_$3]),
-                [eval "AS_TR_SH([cc_save_$2])='${$2}'"
-                 eval "AS_TR_SH([$2])='$3'"
-                 AC_COMPILE_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])],
-                                    [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
-                                    [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
-                 eval "AS_TR_SH([$2])='$cc_save_$2'"])
+          [eval "AS_TR_SH([cc_save_$2])='${$2}'"
+           eval "AS_TR_SH([$2])='-Werror `echo "$3" | sed 's/^-Wno-/-W/'`'"
+           AC_LINK_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; } ])],
+                          [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
+                          [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
+           eval "AS_TR_SH([$2])='$cc_save_$2'"])
 
   AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes],
         [eval "$1='${$1} $3'"])
@@ -66,7 +67,7 @@ AC_DEFUN([CC_CHECK_LDFLAGS], [
     AS_TR_SH([cc_cv_ldflags_$1]),
     [ac_save_LDFLAGS="$LDFLAGS"
      LDFLAGS="$LDFLAGS $1"
-     AC_LINK_IFELSE([AC_LANG_SOURCE([[int main() { return 1; }]])],
+     AC_LINK_IFELSE([int main() { return 1; }],
        [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
        [eval "AS_TR_SH([cc_cv_ldflags_$1])="])
      LDFLAGS="$ac_save_LDFLAGS"
@@ -89,13 +90,13 @@ AC_DEFUN([CC_NOUNDEFINED], [
      *-freebsd* | *-openbsd*) ;;
      *)
         dnl First of all check for the --no-undefined variant of GNU ld. This allows
-        dnl for a much more readable commandline, so that people can understand what
+        dnl for a much more readable command line, so that people can understand what
         dnl it does without going to look for what the heck -z defs does.
         for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do
-          CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])
-         break
+           CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])
+           break
         done
-       ;;
+     ;;
   esac
 
   AC_SUBST([LDFLAGS_NOUNDEFINED])
@@ -231,8 +232,8 @@ AC_DEFUN([CC_FLAG_VISIBILITY], [
     [cc_flag_visibility_save_CFLAGS="$CFLAGS"
      CFLAGS="$CFLAGS $cc_cv_werror"
      CC_CHECK_CFLAGS_SILENT([-fvisibility=hidden],
-       cc_cv_flag_visibility='yes',
-       cc_cv_flag_visibility='no')
+     cc_cv_flag_visibility='yes',
+     cc_cv_flag_visibility='no')
      CFLAGS="$cc_flag_visibility_save_CFLAGS"])
 
   AS_IF([test "x$cc_cv_flag_visibility" = "xyes"],
@@ -252,7 +253,7 @@ AC_DEFUN([CC_FUNC_EXPECT], [
        [int some_function() {
         int a = 3;
         return (int)__builtin_expect(a, 3);
-       }])],
+     }])],
        [cc_cv_func_expect=yes],
        [cc_cv_func_expect=no])
      CFLAGS="$ac_save_CFLAGS"