openssl sets additional cflags in its configuration script. We need to
make it aware of our custom cflags to avoid adding conflicting cflags.
Fixes: #12866
Signed-off-by: Jitao Lu <dianlujitao@gmail.com>
(cherry picked from commit 51f57e7c2dd2799e34036ec74b3436bf490fade0)
e9d2ff8045