Define _XOPEN_SOURCE to 600 consistently for Solaris C99 support

Solaris's header files are very picky about which C compiler can be
used for SUSv3 conformance.  Use of C99 is not compatible with SUSv2
(_XOPEN_SOURCE=500), and C89 is not compatible with SUSv3
(_XOPEN_SOURCE=600).  Since we need some SUSv3 functions, consistently
use SUSv3 so that e2fsprogs will build on Solaris using c99.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
7 files changed