[PATCH v4] gcc-sanitizers: fix -Werror=maybe-uninitialized issue

[<mingli.yu@windriver.com>]

From: Mingli Yu <Mingli.Yu@windriver.com>

When DEBUG_BUILD = "1" added in local.conf, there
comes below build error when "bitbake gcc-sanitizers":
| ./../../../../../../../../work-shared/gcc-8.3.0-r0/gcc-8.3.0/libsanitizer/libbacktrace/../../libbacktrace/elf.c: In function 'elf_is_symlink':
| ../../../../../../../../../work-shared/gcc-8.3.0-r0/gcc-8.3.0/libsanitizer/libbacktrace/../../libbacktrace/elf.c:772:21: error: 'st.st_mode' may be used uninitialized in this function [-Werror=maybe-uninitialized]
|   return S_ISLNK (st.st_mode);

After commit[16643b0322 bitbake.conf: Use -Og in DEBUG_OPTIMIZATION]
introduced, "-Og" added to compiler when debug
build enabled.

Per https://gcc.gnu.org/ml/gcc-patches/2019-04/msg00315.html,
the gcc upstream thinks the warning is a false
positive and suggests to use -O2 rather than -Og
or -O1 when compiling that file, so pass -Wno-error
to compiler when -Og is used to silence the error.

Signed-off-by: Mingli Yu <Mingli.Yu@windriver.com>
---
 meta/recipes-devtools/gcc/gcc-sanitizers.inc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/meta/recipes-devtools/gcc/gcc-sanitizers.inc b/meta/recipes-devtools/gcc/gcc-sanitizers.inc
index e5e8452..8b1d1c9 100644
--- a/meta/recipes-devtools/gcc/gcc-sanitizers.inc
+++ b/meta/recipes-devtools/gcc/gcc-sanitizers.inc
@@ -45,6 +45,9 @@ INHIBIT_DEFAULT_DEPS = "1"
 ALLOW_EMPTY_${PN} = "1"
 DEPENDS = "gcc-runtime virtual/${TARGET_PREFIX}gcc"
 
+# used to fix ../../../../../../../../../work-shared/gcc-8.3.0-r0/gcc-8.3.0/libsanitizer/libbacktrace/../../libbacktrace/elf.c:772:21: error: 'st.st_mode' may be used uninitialized in this function [-Werror=maybe-uninitialized]
+DEBUG_OPTIMIZATION_append = " -Wno-error"
+
 BBCLASSEXTEND = "nativesdk"
 
 PACKAGES = "${PN} ${PN}-dbg"
-- 
2.7.4