Make the -Wno-format-nonliteral flag conditional, and only set in
clang and gcc builds, since this flag is not supported (nor needed)
when building dsw with icc.
Fixes: 46a186b1f0c5 ("event/dsw: add device registration and build system")
Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>