Fix header breakage due to redefining PATH_MAX. The header builtin.h was, incorrectly, redefining PATH_MAX which causes a header order dependency in builtin-write-tree.c. The fix is to simply include <limits.h> directly to obtain the correct definition of PATH_MAX. Signed-off-by: Ramsay Allan Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Junio C Hamano <junkio@cox.net>