symbiotic: use CFLAGS and CPPFLAGS
symbiotic: use CFLAGS and CPPFLAGS

if these variables are passed in environment, let
clang use them. It is handy for setting include paths
and similar

Signed-off-by: Marek Chalupa <a05df156a69ad59faa9af9b666ef78009594c145@gmail.com>

staticafi/symbiotic,staticafi/symbiotic,staticafi/symbiotic,staticafi/symbiotic