infozip: fix cross-compilation issues

- Use CFLAGS from command line

- Remove "Check C compiler type (optimization options)"
  This test force optimization to -O3
  while it is already set in CFLAGS

- Don't use host CPP

- Remove "Check for Large File Support"
  LFS support is already set in CFLAGS

Note: configure script still use host nm

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>