config-uname.mk: use C-only gcc flags only when compiling C sources
config-uname.mk: use C-only gcc flags only when compiling C sources

Move -Werror=incompatible-pointer-types -Werror-implicit-function-declaration
to CONLYFLAGS.

Signed-off-by: Tim Janik <6ec6ff229c4e1c5bbd5933ee92e6c5832ff023bb@gnu.org>

tim-janik/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,tim-janik/beast,swesterfeld/beast,swesterfeld/beast,tim-janik/beast,swesterfeld/beast,tim-janik/beast,swesterfeld/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast