Let gf2x use --libdir and make SAGE_FAT_BINARY work.
Replace symlink in a more portable way.
Make generic build of gf2x smarter.
More fixes for gf2x generic build.
Support SSE2 on x86_64 for gf2x.
Simplify generic build of gf2x.
Properly autoreconfed patches.
Document new gf2x patch.
Prevent autotools to regenerate files.
Simplify gf2x patches
Make the SSE2 stuff work if the compiler does not support SSE2.
Make GSL random distributions initialize with the sage random state functions

This means that Sage's randstate set_random_seed function will make the
GSL distributions also be predictable (for doctests, random matrices, etc.)
Delete #random on some matrix constructor doctests that now depend on Sage's random state
Disable use of weak symbols on Cygwin64 in PPL.
Improve sse2/pclmul detection and enabling
Trac 16855: make finite fields satisfy comparison by identity
Trac 16855: correct option implemention -> impl
Correct derivative of bessel_K
Fix error converting solutions to dict when solving for multiple variables.
Refactor some methods for finite fields elements.