OpenBLAS

ARM: recognize gfortran pre-releases

Without proper recognition of gfortran versions such as
> GNU Fortran (GCC) 4.9.x 20150123 (prerelease)
OpenBLAS assumes the presence of the G77 compiler. Consequently,
`-lgfortran` is missing from the pkg-config file.

The aforementioned compiler is the gfortran compiler in the Android repo
in a commit tagged as `ndk-r14`, cf. Paul Mustière's gfortran build
instructions for Android at https://github.com/buffer51/android-gfortran