It turns out that older gcc (4.9 and 5.4) have gnu++11 support, but
due to a gcc bug fixed in gcc6, throw errors during the build.
The relevant gcc bug is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69959
Version the option based on what gcc we're using.
Signed-off-by: Valdis Kletnieks <valdis.kletni...@vt.edu>
Fixes: 27c287b41659 ("gcc-plugins: fix gcc 11 indigestion with plugins...")
---
diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
index b5487cce69e8..cc779973724a 100644
--- a/scripts/gcc-plugins/Makefile
+++ b/scripts/gcc-plugins/Makefile
@@ -21,8 +21,11 @@ always-y += $(GCC_PLUGIN)
GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)
+# need gnu++11 for gcc 11, but 4.9 and 5.4 need gnu++98
+GCC_FLAVOR = $(call cc-ifversion, -ge, 1100, 11, 98)
+
plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
- -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \
+ -I $(GCC_PLUGINS_DIR)/include -I $(obj)
-std=gnu++$(GCC_FLAVOR) \
-fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
-ggdb -Wno-narrowing -Wno-unused-variable \
-Wno-format-diag
