Macros get from other projects keep their original names:
gl_FSTYPENAME, AX_PATH_LIB_PCRE, etc.
Macros initially writtem for MC have original names with prefix mc_:
mc_VERSION, mc_CHECK_GLIB, etc
Macros get from other projects and modified for MC keep their
original names with prefix mc_:
mc_cu_PREREQ_STAT_PROG, mc_AC_GET_FS_INFO.
Signed-off-by: Andrew Borodin <aborodin@vmail.ru>