gdb/

gdb/
	Code cleanup.
	* amd64-tdep.c (amd64_skip_prologue): Move the XMM code to ...
	(amd64_skip_xmm_prologue): ... this new function.  Describe its
	parameters.  No longer use amd64_prologue_line_bug.
	* defs.h (producer_is_gcc_ge_4): New declaration.
	* dwarf2read.c (producer_is_gcc_ge_4): Move to utils.c.
	(process_full_comp_unit): Update its caller.  Remove
	amd64_prologue_line_bug initialization.
	* symtab.h (struct symtab): Remove field amd64_prologue_line_bug.
	* utils.c (producer_is_gcc_ge_4): Moved here from dwarf2read.c.