re PR c++/13376 (Incorrect dumps of RTL for passes that use current_function_name)
PR c++/13376
* function.h (struct function): Kill `name' field.
(current_function_name): Make it an extern function.
* function.c (current_function_name): New function.
* graph.c: Update all uses of current_function_name.
* gcse.c: Likewise.
* config/alpha/alpha.c, config/avr/avr.c, config/c4x/c4x.c,
config/mips/mips.c, config/pdp11/pdp11.c: Likewise.
* config/ip2k/ip2k.c (function_prologue): Use MAIN_NAME_P
instead of a strcmp with "main".