Fix t-locale.c #define used to avoid a test when using mingw64

The macro __MINGW64_VERSION_MAJOR is defined even when mingw64 is being used to compile 32 bit versions of software with the -m32 switch.

__MINGW64__ is only defined while compiling 64 bit output.
add windows build for sandybridge
add new sqr_basecase code on Windows
add GMP sqr_basecase assembler code for Windows
adjust windows builds for new ser_basecase assembler code
Adjust atom kara_sqr_n crossover.
On nehalem the GMP sqr_basecase is faster. Thus both nehalem and westmere can
use the mpn/x86_64/sqr_basecase.asm file.
Update nehalem tuning values.
Corrected nehalem tuning value.
Merge branch 'master' of https://github.com/wbhart/mpir
Merge remote-tracking branch 'brian/master'
update windows builds for GMP sqr_basecase change
Updated atom tuning values.
Merge branch 'master' of https://github.com/wbhart/mpir
Fix SPEED_DC_DIV_Q_SMALL and add sb_divappr_q to speed.
Switch to using both types of precomputed inverse.
Speed up sb_divappr_q.
Correct SPEED_MPN_DC_DIV_SMALL_Q
Switch to GMP add/submul_1.asm on Penryn.
Improve tail of sb_divappr_q and fix bug.