[network-manager-pptp] build: use m4/compiler_options.m4 from NetworkManager

[Thomas Haller <thaller src gnome org>]

commit 4334f0355a82dfbaeb3fbd2e6a91777ae012715f
Author: Thomas Haller <thaller redhat com>
Date:   Mon Sep 19 10:21:26 2016 +0200

    build: use m4/compiler_options.m4 from NetworkManager
    
    Copy over the m4 macro from NetworkManager repository, it shall replace
    m4/compiler_warnings.m4.

 m4/{compiler_warnings.m4 => compiler_options.m4} |   50 ++++++++++++----------
 1 files changed, 27 insertions(+), 23 deletions(-)
---
diff --git a/m4/compiler_warnings.m4 b/m4/compiler_options.m4
similarity index 76%
rename from m4/compiler_warnings.m4
rename to m4/compiler_options.m4
index 77dcc7a..fa11c52 100644
--- a/m4/compiler_warnings.m4
+++ b/m4/compiler_options.m4
@@ -1,17 +1,17 @@
-dnl Check whether a particular compiler flag works with code provided,
-dnl disable it in CFLAGS if the check fails.
-AC_DEFUN([NM_COMPILER_WARNING], [
+AC_DEFUN([_NM_COMPILER_FLAG], [
        CFLAGS_SAVED="$CFLAGS"
-       CFLAGS="$CFLAGS -Werror -W$1"
-       AC_MSG_CHECKING(whether -W$1 works)
+       CFLAGS="$CFLAGS $GLIB_CFLAGS -Werror $1"
+       AC_MSG_CHECKING([whether $1 works as expected])
 
        AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])], [
                AC_COMPILE_IFELSE([AC_LANG_SOURCE([[$2]])], [
                        AC_MSG_RESULT(yes)
-                       CFLAGS="$CFLAGS_SAVED -W$1"
+                       CFLAGS="$CFLAGS_SAVED"
+                       $3
                ],[
                        AC_MSG_RESULT(no)
-                       CFLAGS="$CFLAGS_SAVED -Wno-$1"
+                       CFLAGS="$CFLAGS_SAVED"
+                       $4
                ])
        ],[
                AC_MSG_RESULT(not supported)
@@ -19,6 +19,21 @@ AC_DEFUN([NM_COMPILER_WARNING], [
        ])
 ])
 
+dnl Check whether a particular compiler flag is supported,
+dnl add it to CFLAGS if it is
+AC_DEFUN([NM_COMPILER_FLAG], [
+        _NM_COMPILER_FLAG([$1], [], [
+               CFLAGS="$CFLAGS $1"
+               $2
+       ], [$3])
+])
+
+dnl Check whether a particular warning is not emitted with code provided,
+dnl disable it in CFLAGS if the check fails.
+AC_DEFUN([NM_COMPILER_WARNING], [
+        _NM_COMPILER_FLAG([-W$1], [$2], [CFLAGS="$CFLAGS -W$1"], [CFLAGS="$CFLAGS -Wno-$1"])
+])
+
 AC_DEFUN([NM_COMPILER_WARNINGS],
 [AC_ARG_ENABLE(more-warnings,
        AS_HELP_STRING([--enable-more-warnings], [Possible values: no/yes/error]),
@@ -40,7 +55,6 @@ if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
        dnl attach it to the CFLAGS.
        NM_COMPILER_WARNING([unknown-warning-option], [])
 
-       CFLAGS_SAVED="$CFLAGS"
        CFLAGS_MORE_WARNINGS="-Wall -std=gnu89"
 
        if test "x$set_more_warnings" = xerror; then
@@ -52,27 +66,17 @@ if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
                      -Wfloat-equal -Wno-unused-parameter -Wno-sign-compare \
                      -Wno-duplicate-decl-specifier \
                      -Wstrict-prototypes \
-                     -fno-strict-aliasing -Wno-unused-but-set-variable \
+                     -Wno-unused-but-set-variable \
+                     -Wno-format-y2k \
                      -Wundef -Wimplicit-function-declaration \
-                     -Wpointer-arith -Winit-self \
+                     -Wpointer-arith -Winit-self -Wformat-nonliteral \
                      -Wmissing-include-dirs -Wno-pragmas; do
                dnl GCC 4.4 does not warn when checking for -Wno-* flags 
(https://gcc.gnu.org/wiki/FAQ#wnowarning)
-               CFLAGS="-Werror $CFLAGS_MORE_WARNINGS $(printf '%s' "$option" | sed 's/^-Wno-/-W/')  
$CFLAGS_SAVED"
-               AC_MSG_CHECKING([whether compiler understands $option])
-               AC_TRY_COMPILE([], [],
-                       has_option=yes,
-                       has_option=no,)
-               if test $has_option != no; then
-                       CFLAGS_MORE_WARNINGS="$CFLAGS_MORE_WARNINGS $option"
-               fi
-               AC_MSG_RESULT($has_option)
-               unset has_option
+                _NM_COMPILER_FLAG([$(printf '%s' "$option" | sed 's/^-Wno-/-W/')], [],
+                                 [CFLAGS_MORE_WARNINGS="$CFLAGS_MORE_WARNINGS $option"], [])
        done
        unset option
 
-       CFLAGS="$CFLAGS_SAVED"
-       unset CFLAGS_SAVED
-
        dnl Disable warnings triggered by known compiler problems
 
        dnl https://bugzilla.gnome.org/show_bug.cgi?id=745821