rerere: Separate libgit and builtin functions This patch moves rerere()-related functions into a newly created rerere.c file. The setup_rerere() function is needed by both rerere() and cmd_rerere(), so this function is moved to rerere.c and declared non-static (and "extern") in newly created rerere.h file. Signed-off-by: Stephan Beyer <s-beyer@gmx.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>