dnl CF_GCC_WARNINGS version: 29 updated: 2012/06/16 14:55:39
dnl ---------------
dnl Check if the compiler supports useful warning options.  There's a few that
dnl we don't use, simply because they're too noisy:
dnl
dnl	-Wconversion (useful in older versions of gcc, but not in gcc 2.7.x)
dnl	-Wredundant-decls (system headers make this too noisy)
dnl	-Wtraditional (combines too many unrelated messages, only a few useful)
dnl	-Wwrite-strings (too noisy, but should review occasionally).  This
dnl		is enabled for ncurses using "--enable-const".
dnl	-pedantic
dnl
dnl Parameter:
dnl	$1 is an optional list of gcc warning flags that a particular
dnl		application might want to use, e.g., "no-unused" for
dnl		-Wno-unused
dnl Special:
dnl	If $with_ext_const is "yes", add a check for -Wwrite-strings
dnl
AC_DEFUN([CF_GCC_WARNINGS],
[
AC_REQUIRE([CF_GCC_VERSION])
CF_INTEL_COMPILER(GCC,INTEL_COMPILER,CFLAGS)
CF_CLANG_COMPILER(GCC,CLANG_COMPILER,CFLAGS)

cat > conftest.$ac_ext <<EOF
#line __oline__ "${as_me:-configure}"
int main(int argc, char *argv[[]]) { return (argv[[argc-1]] == 0) ; }
EOF

if test "$INTEL_COMPILER" = yes
then
# The "-wdXXX" options suppress warnings:
# remark #1419: external declaration in primary source file
# remark #1683: explicit conversion of a 64-bit integral type to a smaller integral type (potential portability problem)
# remark #1684: conversion from pointer to same-sized integral type (potential portability problem)
# remark #193: zero used for undefined preprocessing identifier
# remark #593: variable "curs_sb_left_arrow" was set but never used
# remark #810: conversion from "int" to "Dimension={unsigned short}" may lose significant bits
# remark #869: parameter "tw" was never referenced
# remark #981: operands are evaluated in unspecified order
# warning #279: controlling expression is constant

	AC_CHECKING([for $CC warning options])
	cf_save_CFLAGS="$CFLAGS"
	EXTRA_CFLAGS="-Wall"
	for cf_opt in \
		wd1419 \
		wd1683 \
		wd1684 \
		wd193 \
		wd593 \
		wd279 \
		wd810 \
		wd869 \
		wd981
	do
		CFLAGS="$cf_save_CFLAGS $EXTRA_CFLAGS -$cf_opt"
		if AC_TRY_EVAL(ac_compile); then
			test -n "$verbose" && AC_MSG_RESULT(... -$cf_opt)
			EXTRA_CFLAGS="$EXTRA_CFLAGS -$cf_opt"
		fi
	done
	CFLAGS="$cf_save_CFLAGS"

elif test "$GCC" = yes
then
	AC_CHECKING([for $CC warning options])
	cf_save_CFLAGS="$CFLAGS"
	EXTRA_CFLAGS=
	cf_warn_CONST=""
	test "$with_ext_const" = yes && cf_warn_CONST="Wwrite-strings"
	for cf_opt in W Wall \
		Wbad-function-cast \
		Wcast-align \
		Wcast-qual \
		Winline \
		Wmissing-declarations \
		Wmissing-prototypes \
		Wnested-externs \
		Wpointer-arith \
		Wshadow \
		Wstrict-prototypes \
		Wundef $cf_warn_CONST $1
	do
		CFLAGS="$cf_save_CFLAGS $EXTRA_CFLAGS -$cf_opt"
		if AC_TRY_EVAL(ac_compile); then
			test -n "$verbose" && AC_MSG_RESULT(... -$cf_opt)
			case $cf_opt in #(vi
			Wcast-qual) #(vi
				CPPFLAGS="$CPPFLAGS -DXTSTRINGDEFINES"
				;;
			Winline) #(vi
				case $GCC_VERSION in
				[[34]].*)
					CF_VERBOSE(feature is broken in gcc $GCC_VERSION)
					continue;;
				esac
				;;
			Wpointer-arith) #(vi
				case $GCC_VERSION in
				[[12]].*)
					CF_VERBOSE(feature is broken in gcc $GCC_VERSION)
					continue;;
				esac
				;;
			esac
			EXTRA_CFLAGS="$EXTRA_CFLAGS -$cf_opt"
		fi
	done
	CFLAGS="$cf_save_CFLAGS"
fi
rm -rf conftest*

AC_SUBST(EXTRA_CFLAGS)
])dnl
