Reduce more headers

[albinahlback]

• Remove string.h inclusion from mpoly.h by making mpoly_copy_monomials, but still providing a symbol.
• Remove some unnecessary ulong_extras.h inclusions.
• Cleanup fmpz_vec.h.
• Merge the trigonometric series source files in nmod_poly.
• Write a proper function for fmpz_mul2_uiui and deinline fmpz_divexact2_uiui (with a slight modification for GNU compilers).
• Remove longlong.h inclusion from fmpz.h.
• Simplify MAG_FIXMUL for 32-bit systems, so one can remove longlong.h inclusion there completely.
• Reduce arb_mat.h and acb_mat.h via deinlining and removing, now, redundant headers.
• Convert n_[cf]log(X, 2) to FLINT_[CF]LOG2(X)
• Remove acb.h inclusion from acb_dirichlet.h

[fredrik-johansson]

It's annoying to have to include specific system headers before header files to use standard functions, e.g. <string.h> before <mpoly.h> for mpoly_copy_monomials. We might as well deinline, or replace memcpy with a loop.

[albinahlback]

It's annoying to have to include specific system headers before header files to use standard functions, e.g. <string.h> before <mpoly.h> for mpoly_copy_monomials. We might as well deinline, or replace memcpy with a loop.

How about something like

#if BUILDING_FLINT
# define mpoly_copy_monomials(bla...) ...
#else
/* Declare symbol */
#endif

So that it actually evaluate to memcpy when building the library?

[fredrik-johansson]

-1 to BUILDING_FLINT.

If the string.h inclusion is a problem, not inlining this function seems like the easiest solution.

[albinahlback]

I think this is the best solution. If the compiler is GCC compatible, it will provide __builtin_memcpy, and so we simply expand to that. Otherwise, just use the symbol.