Skip this test if if_tap module is not available

PR:		236842
Approved by:	asomers
MFC after:	1 month
Sponsored by:	Netflix

tests/sys/netmap/Makefile

@@ -7,6 +7,7 @@ TEST_METADATA+=	required_user="root"
 TEST_METADATA+=	is_exclusive=true
 
 LDFLAGS+= 	-lpthread
+CFLAGS+=	-I${SRCTOP}/tests
 PLAIN_TESTS_C+=	ctrl-api-test
 
 WARNS?=		6

tests/sys/netmap/ctrl-api-test.c

@@ -48,9 +48,15 @@
 #include <unistd.h>
 #include <signal.h>
 
+#ifdef __FreeBSD__
+#include "freebsd_test_suite/macros.h"
+#endif
+
+
 #ifdef __linux__
 #include <sys/eventfd.h>
 #else
+
 static int
 eventfd(int x __unused, int y __unused)
 {
@@ -1831,6 +1837,10 @@ main(int argc, char **argv)
 	int opt;
 	int i;
 
+#ifdef __FreeBSD__
+	PLAIN_REQUIRE_KERNEL_MODULE("if_tap", 0);
+#endif
+
 	memset(&ctx_, 0, sizeof(ctx_));
 
 	{