Further pre-update cleanups for `lang/ocaml':

• Do not suppress .bak-files when patching things with ``sed(1) -i'', those can be useful for debugging and catching no-ops
• Drop `files/manfiles', it is no longer used (looks like a relic from pre-staging times)
• Do not pass ``-as "${AS} ${ASFLAGS}"'' in the initial CONFIGURE_ARGS: when ARM support was added in r361233, appropriate values are passed conditionally (subject to ${ARCH}), see line 69
• Simplify handling of CFLAGS (obtained from RedHat package): rather than passing them as part of the compiler and "fixing" one generated Makefile in `post-configure', teach the configure script about them