[mm-common] Clean up MM_ARG_ENABLE_WARNINGS() documentation

[Daniel Elstner <daniel src gnome org>]

commit d5e4c7d07bdee03559c9dd36d72a4cdb5a5b5658
Author: Daniel Elstner <daniel kitta gmail com>
Date:   Wed Nov 4 20:32:06 2009 +0100

    Clean up MM_ARG_ENABLE_WARNINGS() documentation
    
    * macros/mm-warnings.m4 (MM_ARG_ENABLE_WARNINGS): Refine usage example
    and reduce verbosity.

 macros/mm-warnings.m4 |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)
---
diff --git a/macros/mm-warnings.m4 b/macros/mm-warnings.m4
index 12ee7b9..ca2645d 100644
--- a/macros/mm-warnings.m4
+++ b/macros/mm-warnings.m4
@@ -15,7 +15,7 @@
 ## You should have received a copy of the GNU General Public License
 ## along with mm-common.  If not, see <http://www.gnu.org/licenses/>.
 
-#serial 20090910
+#serial 20091103
 
 ## _MM_ARG_ENABLE_WARNINGS_OPTION
 ##
@@ -45,18 +45,24 @@ AC_ARG_ENABLE([warnings],
 ## are enabled, too.
 ##
 ## For instance, your configure.ac file might use the macro like this:
-##   MM_ARG_ENABLE_WARNINGS([MYAPP_C_WARNING_FLAGS],
-##                         [-Wall],
-##                         [-pedantic -Wall -Wextra]
-##                         [G PANGO ATK GDK GDK_PIXBUF GTK])
+##
+##   MM_ARG_ENABLE_WARNINGS([EXAMPLE_WFLAGS],
+##                          [-Wall],
+##                          [-pedantic -Wall -Wextra],
+##                          [G PANGO ATK GDK GDK_PIXBUF GTK])
 ##
 ## Your Makefile.am could then contain a line such as this:
-##   AM_CFLAGS = $(MYAPP_C_WARNING_FLAGS)
 ##
-## Note that you may call MM_ARG_ENABLE_WARNINGS twice, once for CFLAGS, and once for CXXFLAGS (for C++).
+##   AM_CFLAGS = $(EXAMPLE_WFLAGS)
+##
+## In order to determine the warning options to use with the C++ compiler,
+## call AC_LANG([C++]) first to change the current language.  If different
+## output variables are used, it is also fine to call MM_ARG_ENABLE_WARNINGS
+## repeatedly, once for each language setting.
 ##
-## You may force people to fix warnings when creating release tarballs by 
+## You may force people to fix warnings when creating release tarballs by
 ## adding this line to your Makefile.am:
+##
 ##   DISTCHECK_CONFIGURE_FLAGS = --enable-warnings=fatal
 ##
 AC_DEFUN([MM_ARG_ENABLE_WARNINGS],