* config/tc-alpha.c: Added various prototypes for static functions.

* config/tc-alpha.c: Added various prototypes for static functions.
(in_range): New function, tests whether a value can fit in an N-bit field.
(build_mem, build_operate_n): New functions for constructing opcode values.
(emit_sll_n, emit_ldah_num, emit_addq_r, emit_lda_n): New functions for
emitting single instructions, no longer requiring a recursive call to
md_assemble.
(emit_add64): New function for expanding a REG:=REG+CONST operation into
one or more instructions, to handle wide constants.
(clear_insn): New variable.
(md_begin): Fill it in with zeros and BFD_RELOC_NONE values.
(alpha_ip): Use it to initialize local variable insns.
(alpha_ip, label "immediate" and cases 'P', 'G'): Use emit_add64 for
calculations.