Added dependencies for extensions.
Change directory creations in Makefile.in.
Use tabs everywhere in Makefile.in.
Merge xgcd_partial from qfb branch.
Added prototype for xgcd_partial to fmpz.h.
Add missing const to prototype.
Fix for directory creations.
Fix bug in fmpz_is_prime_pseudosquare on 32 bit machine.
Use slong instead of long in _si function prototypes.
Merge branch 'trunk' into build_system