glibc-2.28 complains:
configure: error: use a compatible toolchain or configure with --disable-mathvec (this results in incomplete ABI).
Apparently this is a problem in the way GCC passes the -mcpu and -march
values to the assembler. As a workaround have the configure check pass
-mcpu as well to override anything we're passing in the environment.
Patch and explanation taken from the Yocto project with thanks.
Signed-off-by: Chris Packham <judge.packham@gmail.com>