From b729ed01093312cef7ce48d07b13e225b25446db Mon Sep 17 00:00:00 2001
From: Dan McGee <dan@archlinux.org>
Date: Sat, 7 Apr 2012 13:03:41 -0500
Subject: Add a new configure option for excessive compiler warning flags

This adds a bunch of warning flags to the list used when compiling.

Signed-off-by: Dan McGee <dan@archlinux.org>
---
 configure.ac    | 41 +++++++++++++++++++++++++++++++++++++++++
 m4/acinclude.m4 | 20 ++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/configure.ac b/configure.ac
index 98e6af1d..b31b58a8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -128,6 +128,11 @@ AC_ARG_ENABLE(debug,
 	AS_HELP_STRING([--enable-debug], [enable debugging support]),
 	[debug=$enableval], [debug=no])
 
+# Help line for compiler warning flags
+AC_ARG_ENABLE(warningflags,
+	AS_HELP_STRING([--enable-warningflags], [enable extra compiler warning flags]),
+	[warningflags=$enableval], [warningflags=no])
+
 # Help line for using git version in pacman version string
 AC_ARG_ENABLE(git-version,
 	AS_HELP_STRING([--enable-git-version],
@@ -354,6 +359,40 @@ else
 	WARNING_CFLAGS="-Wall"
 fi
 
+# Enable or disable compiler warning flags
+AC_MSG_CHECKING(for excessive compiler warning flags)
+if test "x$warningflags" = "xyes" ; then
+	AC_MSG_RESULT(yes)
+	CFLAGS_ADD([-Wcast-align], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wclobbered], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wempty-body], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wfloat-equal], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wformat-nonliteral], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wformat-security], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wignored-qualifiers], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Winit-self], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wlogical-op], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wmissing-declarations], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wmissing-parameter-type], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wmissing-prototypes], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wold-style-declaration], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Woverride-init], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wpointer-arith], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wredundant-decls], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wshadow], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wsign-compare], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wstrict-aliasing], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wstrict-overflow=5], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wstrict-prototypes], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wtype-limits], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wuninitialized], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wunused-but-set-parameter], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wunused-parameter], [WARNING_CFLAGS])
+	CFLAGS_ADD([-Wwrite-strings], [WARNING_CFLAGS])
+else
+	AC_MSG_RESULT(no)
+fi
+
 # Enable or disable use of git version in pacman version string
 AC_MSG_CHECKING(whether to use git version if available)
 if test "x$wantgitver" = "xyes" ; then
@@ -450,6 +489,8 @@ ${PACKAGE_NAME}:
     Run make in doc/ dir   : ${wantdoc} ${asciidoc}
     Doxygen support        : ${usedoxygen}
     debug support          : ${debug}
+    extra warning flags    : ${warningflags}
+    use git version        : ${wantgitver}
 "
 
 # vim:set ts=2 sw=2 noet:
diff --git a/m4/acinclude.m4 b/m4/acinclude.m4
index df4f83a4..8ea45973 100644
--- a/m4/acinclude.m4
+++ b/m4/acinclude.m4
@@ -101,6 +101,26 @@ AC_DEFUN([GCC_GNU89_INLINE_CC],[
   fi
 ])
 
+dnl CFLAGS_ADD(PARAMETER, VARIABLE)
+dnl Adds parameter to VARIABLE if the compiler supports it.  For example,
+dnl CFLAGS_ADD([-Wall],[WARN_FLAGS]).
+AC_DEFUN([CFLAGS_ADD],
+[AS_VAR_PUSHDEF([my_cflags], [cflags_cv_warn_$1])dnl
+AC_CACHE_CHECK([whether compiler handles $1], [my_cflags], [
+  save_CFLAGS="$CFLAGS"
+  CFLAGS="${CFLAGS} $1"
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],
+                    [AS_VAR_SET([my_cflags], [yes])],
+                    [AS_VAR_SET([my_cflags], [no])])
+  CFLAGS="$save_CFLAGS"
+])
+AS_VAR_PUSHDEF([new_cflags], [[$2]])dnl
+AS_VAR_IF([my_cflags], [yes], [AS_VAR_APPEND([new_cflags], [" $1"])])
+AS_VAR_POPDEF([new_cflags])dnl
+AS_VAR_POPDEF([my_cflags])dnl
+m4_ifval([$2], [AS_LITERAL_IF([$2], [AC_SUBST([$2])], [])])dnl
+])
+
 dnl Checks for getmntinfo and determines whether it uses statfs or statvfs
 AC_DEFUN([FS_STATS_TYPE],
   [AC_CACHE_CHECK([filesystem statistics type], fs_stats_cv_type,
-- 
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