[MIPS 3/30] Reorder functions and remove forward statics

[Richard Sandiford <rsandifo at nildram dot co dot uk>]

This patch just moves code around and puts the targetm initialiser at
the end of the file.  The main aim is to remove the forward statics
(long overdue), but I've also tried to group functions into more
logical groups.

Some of the function definitions were missing "static", instead relying
on the staticness of the declaration.  There should be no other code
changes.

I've also moved the mips.h variable declarations to the end of the file
and enclosed them all in #ifndef USED_FOR_TARGET.  This is needed for
later char->bool changes.

Richard

gcc/
	* config/mips/mips.h: Move variable declarations to end of file and
	enclose them all in #ifndef USED_FOR_TARGET.
	* config/mips/mips.c: Reorder functions into more logical groups,
	and so that callees appear before callers.  Put the targetm
	initializer at the end of the file.  Remove forward static
	declarations where possible.
	(mips_init_builtins): Add "static" to definition.
	(mips_expand_builtin, mips_mode_rep_extended): Likewise.

[patch is huge and unreadable]