re enable Fortran optimization flag on windows

[tkelman]

partial revert of 299cdcd
from #696, was not explained why that was needed cc @wernsaar

[xianyi]

@tkelman , did you run lapack test on windows?

[tkelman]

Not yet. I'll try to remember to do that when I have a moment. Keep reminding me every few days until I do.

[tkelman]

I couldn't figure out how to run lapack's tests directly, but all of Julia's tests pass on an i7-6700HQ, windows 64 bit build of openblas commit 5fef0d1

[martin-frbg]

"make lapack-test" probably, or are you using an IDE rather than a plain makefile environment ?

[tkelman]

using makefiles, but with the build configuration customized as julia needs. I'm also cross compiling from cygwin which the test scripts might not be written in a way that can handle, but I'll give it a try.

[tkelman]

                        -->   LAPACK TESTING SUMMARY  <--
SUMMARY                 nb test run     numerical error         other error
================        ===========     =================       ================
REAL                    1169109         0       (0.000%)        0       (0.000%)
DOUBLE PRECISION        1169921         0       (0.000%)        0       (0.000%)
COMPLEX                 633152          0       (0.000%)        0       (0.000%)
COMPLEX16               633964          0       (0.000%)        0       (0.000%)

--> ALL PRECISIONS      3606146         0       (0.000%)        0       (0.000%)