Suppress warnings about 'warn_unused_result' attribute directive

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/configure b/configure
index ca6d45c612..7775b1b423 100755
--- a/configure
+++ b/configure
@@ -1667,6 +1667,23 @@ if compile_prog "" "" ; then
 fi
 
 ##########################################
+# check if the compiler understands attribute warn_unused_result
+#
+# This could be smarter, but gcc -Werror does not error out even when warning
+# about attribute warn_unused_result
+
+gcc_attribute_warn_unused_result=no
+cat > $TMPC << EOF
+#if defined(__GNUC__) && (__GNUC__ < 4) && defined(__GNUC_MINOR__) && (__GNUC__ < 4)
+#error gcc 3.3 or older
+#endif
+int main(void) { return 0;}
+EOF
+if compile_prog "" ""; then
+    gcc_attribute_warn_unused_result=yes
+fi
+
+##########################################
 # check if we have fdatasync
 
 fdatasync=no
@@ -1994,6 +2011,9 @@ fi
 if test "$need_offsetof" = "yes" ; then
   echo "CONFIG_NEED_OFFSETOF=y" >> $config_host_mak
 fi
+if test "$gcc_attribute_warn_unused_result" = "yes" ; then
+  echo "CONFIG_GCC_ATTRIBUTE_WARN_UNUSED_RESULT=y" >> $config_host_mak
+fi
 if test "$fdatasync" = "yes" ; then
   echo "CONFIG_FDATASYNC=y" >> $config_host_mak
 fi