configure: don't turn some warnings into errors

Do not turn some compiler warnings into errors by default. This part was
copied from openbsc.git 34f012 ("Turn some compiler warnings into
errors"), where it was added before --enable-werror was available.

We build with --enable-werror during development and in CI. If the code
is built with a different compiler that throws additional warnings, it
should not stop the build.

Related: OS#5289
Change-Id: I22f6f4d3d4b81d4791a72a7bce130035bef58c31
1 file changed