[gnome-common] compiler-warnings: code cleanup: Extract common warnings into variables

[Colin Walters <walters src gnome org>]

commit afad58ce8302acbff204685ae2df20f118753deb
Author: Colin Walters <walters verbum org>
Date:   Mon Nov 12 15:00:06 2012 -0500

    compiler-warnings: code cleanup: Extract common warnings into variables
    
    Will make future refactoring clearer, and also we have comments now.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=688192

 macros2/gnome-compiler-flags.m4 |   43 ++++++++++++++++++++------------------
 1 files changed, 23 insertions(+), 20 deletions(-)
---
diff --git a/macros2/gnome-compiler-flags.m4 b/macros2/gnome-compiler-flags.m4
index 992ad5c..c4cc1c6 100644
--- a/macros2/gnome-compiler-flags.m4
+++ b/macros2/gnome-compiler-flags.m4
@@ -19,6 +19,27 @@ AC_DEFUN([GNOME_COMPILE_WARNINGS],[
     warning_flags=
     realsave_CFLAGS="$CFLAGS"
 
+    dnl These are warning flags that aren't marked as fatal.  Can be
+    dnl overridden on a per-project basis with -Wno-foo.
+    base_warn_flags=" \
+        -Wall \
+	-Wstrict-prototypes \
+    "
+
+    dnl These compiler flags typically indicate very broken or suspicious
+    dnl code.  Some of them such as implicit-function-declaration are
+    dnl just not default because gcc compiles a lot of legacy code.
+    dnl We choose to make this set into explicit errors.
+    base_error_flags=" \
+	-Werror=missing-prototypes \
+	-Werror=implicit-function-declaration \
+	-Werror=pointer-arith \
+	-Werror=init-self \
+	-Werror=format-security \
+	-Werror=format=2 \
+	-Werror=missing-include-dirs \
+    "
+
     case "$enable_compile_warnings" in
     no)
 	warning_flags=
@@ -27,29 +48,11 @@ AC_DEFUN([GNOME_COMPILE_WARNINGS],[
 	warning_flags="-Wall"
 	;;
     yes)
-	warning_flags="\
-	-Wall \
- 	-Wstrict-prototypes \
-	-Werror=missing-prototypes \
-	-Werror=implicit-function-declaration \
-	-Werror=pointer-arith \
-	-Werror=init-self \
-	-Werror=format-security \
-	-Werror=format=2 \
-	-Werror=missing-include-dirs"
+	warning_flags="$base_warn_flags $base_error_flags"
 	;;
     maximum|error)
-	warning_flags="\
-	-Wall \
-	-Wstrict-prototypes \
+	warning_flags="$base_warn_flags $base_error_flags \
 	-Wdeclaration-after-statement \
-	-Werror=missing-prototypes \
-	-Werror=implicit-function-declaration \
-	-Werror=pointer-arith \
-	-Werror=init-self \
-	-Werror=format-security \
-	-Werror=format=2 \
-	-Werror=missing-include-dirs \
 	-Wnested-externs \
 	-Wno-sign-compare"
 	;;