Perform all the actions of AC_HEADER_DIRENT (see Particular Headers). Then, if struct dirent contains a d_ino member, define HAVE_STRUCT_DIRENT_D_INO.

HAVE_STRUCT_DIRENT_D_INO indicates only the presence of d_ino, not whether its contents are always reliable. Traditionally, a zero d_ino indicated a deleted directory entry, though current systems hide this detail from the user and never return zero d_ino values. Many current systems report an incorrect d_ino for a directory entry that is a mount point.

Perform all the actions of AC_HEADER_DIRENT (see Particular Headers). Then, if struct dirent contains a d_type member, define HAVE_STRUCT_DIRENT_D_TYPE.

If struct stat contains an st_blksize member, define HAVE_STRUCT_STAT_ST_BLKSIZE. The former name, HAVE_ST_BLKSIZE is to be avoided, as its support will cease in the future. This macro is obsoleted, and should be replaced by

          AC_CHECK_MEMBERS([struct stat.st_blksize])
     

If struct stat contains an st_blocks member, define HAVE_STRUCT_STAT_ST_BLOCKS. Otherwise, require an AC_LIBOBJ replacement of ‘fileblocks’. The former name, HAVE_ST_BLOCKS is to be avoided, as its support will cease in the future.

If struct stat contains an st_rdev member, define HAVE_STRUCT_STAT_ST_RDEV. The former name for this macro, HAVE_ST_RDEV, is to be avoided as it will cease to be supported in the future. Actually, even the new macro is obsolete and should be replaced by:

          AC_CHECK_MEMBERS([struct stat.st_rdev])
     

If time.h does not define struct tm, define TM_IN_SYS_TIME, which means that including sys/time.h had better define struct tm.

This macro is obsolescent, as time.h defines struct tm in current systems. New programs need not use this macro.

Figure out how to get the current timezone. If struct tm has a tm_zone member, define HAVE_STRUCT_TM_TM_ZONE (and the obsoleted HAVE_TM_ZONE). Otherwise, if the external array tzname is found, define HAVE_TZNAME; if it is declared, define HAVE_DECL_TZNAME.