gc/bits.c
. improved format with associated cast;
gc/closure.c
gc/dcl.c
gc/range.c
gc/reflect.c
gc/sinit.c
. dropped unnecessary assignments;
gc/gen.c
. dropped unnecessary assignment;
. added static qualifier to local function definition;
gc/go.h
. added varargck pragmas;
gc/lex.c
. used {} instead of ; in if statement to suppress warning;
. replaced exit(0) with exits(0);
. added compilation conditions for SIGBUS/SIGSEGV;
. dropped unnecessary assignment;
gc/mparith2.c
. dropped four unnecessary assignments/initialisations;
gc/obj.c
. added type cast to local pointer;
gc/pgen.c
. added cast and related print format;
gc/subr.c
. replaced exit(1) with exits("error");
. replaced unlink() with remove();
. renamed local cistrmp() as ucistrmp() to remove conflict with
  Plan 9 function by the same name;
gc/swt.c
. added braces instead of ; as empty statment;
gc/typecheck.c
. added static qualifier to local function definition;
. dropped unnecessary assignments;
gc/walk.c
. dropped unnecessary assignments;
. added static qualifier to local function definitions;

R=rsc
CC=golang-dev
https://golang.org/cl/4964046