xfstests: fix build errors and warnings

After upgrading userspace on test machines to xfsprogs-4.2.0-rc1,
lots of build warnings and failures are exposed from implicit
includes that no longer exist. Hence these need fixing to allow
fstests to build correctly.

gcc also seems to have grown new stupidities around uninitialised
variables, so fix them while touching the same files.

Signed-off-by: Dave Chinner <david@fromorbit.com>

dmapi/src/common/cmd/write_invis.c

@@ -18,6 +18,7 @@
 
 #include <lib/hsm.h>
 
+#include <unistd.h>
 #include <string.h>
 #include <malloc.h>
 #include <getopt.h>

dmapi/src/common/lib/util.c

@@ -23,6 +23,7 @@
 
 #include <unistd.h>
 #include <stdarg.h>
+#include <ctype.h>
 
 #include <lib/hsm.h>
 

dmapi/src/suite1/cmd/get_dirattrs.c

@@ -17,6 +17,7 @@
  */
 
 #include <lib/hsm.h>
+#include <string.h>
 
 /*---------------------------------------------------------------------------
 

dmapi/src/suite1/cmd/probe_punch_xfsctl_hole.c

@@ -18,8 +18,11 @@
 
 #include <lib/hsm.h>
 
+#include <unistd.h>
 #include <getopt.h>
 #include <string.h>
+#include <fcntl.h>
+
 
 
 /*---------------------------------------------------------------------------

dmapi/src/suite2/src/test_dmattr.c

@@ -16,6 +16,7 @@
  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>