Merge pull request #14 from sebastien-villemot/master

Patch currently applied to the Debian package
use C11 CMPLX or gcc __builtin_complex if available to define cpack macros
added Faddeeva package from http://ab-initio.mit.edu/Faddeeva for complex error functions
Merge pull request #16 from stevengj/CMPLX

use C11 CMPLX or gcc __builtin_complex; this fixes issue #15
Merge pull request #17 from stevengj/Faddeeva

add Faddeeva package from http://ab-initio.mit.edu/Faddeeva
use $(AR) variable instead of ar
Add Makefile.extras to build libopenlibm-extras.
Replace amos with slatec
Add Makefile.extras
Build libopenlibm-extras separately
Reinstate amos for now, since slatec is giving some trouble.
support environment CFLAGS (and SFLAGS) without clobbering the essential build flags
add exported names for ldexp
fix amd64 asm syntax for windows
add special cases for powers 3 and 4, in addition to 2
Remove  slatec since we do not use it.
fix WINNT autodetection
do ARCH autodetection based upon compiler instead of host
unsupport the mingw32 compiler
add i486 processor ARCH detection
fix calling convention on win64, mostly passing the numerical tests