There is absolutely no reason not to include <string.h> globally, and
with the inline function for mempcpy() we need it there anyway.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
nasmlib.c had basically turned into a garbage bin of various functions
with very little in common. Break it up into logical components for
isolation and manageability.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>