STAR_LARGEFILE_SUPPORT
Set macros for compiling C routines that want to make use of
large file support. This is a joining of
AC_SYS_LARGEFILE and AC_FUNC_FSEEKO so
defines the macros _FILE_OFFSET_BITS,
_LARGEFILE_SOURCE and _LARGE_FILES as
needed , along with HAVE_FSEEKO when
fseeko and ftello are available.
To use large file support you need to use fseeko and ftello,
instead of fseek and ftell, when HAVE_FSEEKO is defined
(and use type off_t for offsets) and compile all C code
with the other defines (many of the usual system calls are replaced
with large file supporting ones, when this is done).
Currently the AC_FUNC_FSEEKO macro does not define
_LARGEFILE_SOURCE under Solaris, so this function makes
sure that this is done. It also gathers the values of
_FILE_OFFSET_BITS, _LARGEFILE_SOURCE and
_LARGE_FILES and sets the
STAR_LARGEFILE_CFLAGS variable so that it can be used
as part of CFLAGS when compiling. This in useful for passing to
packages which are not directly part of the starconf system. Note
that normally the necessary defines are written to
config.h or are already made part of the local
CFLAGS, so this variable is not needed.