Add ATF_REQUIRE_FEATURE and PLAIN_REQUIRE_FEATURE macros for

testing for kernel features via the feature_present(3) libcall

The semantics are similar to the other macros in the header (skip
testcase with ATF macro; exit with appropriate exit code with the
PLAIN macro)

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

tests/freebsd_test_suite/macros.h

@@ -38,6 +38,13 @@
 
 #include <atf-c.h>
 
+#define	ATF_REQUIRE_FEATURE(_feature_name) do {				\
+	if (feature_present(_feature_name) == 0) {			\
+		atf_tc_skip("kernel feature (%s) not present",		\
+		    _feature_name);					\
+	}								\
+} while(0)
+
 #define	ATF_REQUIRE_KERNEL_MODULE(_mod_name) do {			\
 	if (modfind(_mod_name) == -1) {					\
 		atf_tc_skip("module %s could not be resolved: %s",	\
@@ -45,6 +52,14 @@
 	}								\
 } while(0)
 
+#define	PLAIN_REQUIRE_FEATURE(_feature_name, _exit_code) do {		\
+	if (feature_present(_feature_name) == 0) {			\
+		printf("kernel feature (%s) not present\n",		\
+		    _feature_name);					\
+		_exit(_exit_code);					\
+	}								\
+} while(0)
+
 #define	PLAIN_REQUIRE_KERNEL_MODULE(_mod_name, _exit_code) do {		\
 	if (modfind(_mod_name) == -1) {					\
 		printf("module %s could not be resolved: %s\n",		\