[cooker] Some configure scripts may be broken with LTO


i've noticed in two cases of gmp and mpfr that if LTO is used when
configure is executed then it produces wrong checks.

For example in gmp

checking format of `double' floating point... unknown
BUILDSTDERR: configure: WARNING: Could not determine float format.
BUILDSTDERR: configure: WARNING: Conversions to and from "double" may be slow.

I had to do this to fix it:

I wonder how many packages are wrong configured. Is there any way to
fix this better way? Maybe pushing -flto on %make_build ?