Added `test` make target & test program.

Fortune for memfd_secret-shim's current commit: Half curse − 半凶

.gitignore

@@ -5,6 +5,7 @@ perf/
 *.o
 *-debug
 *-release
+*-test
 *.so
 *.so.*
 *.gch

src/test/main.c

@@ -0,0 +1,21 @@
+
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+
+#include <memfd_secret.h>
+
+int main()
+{
+	int fd = memfd_secret(0);
+
+	if(fd < 0) {
+		perror("memfd_secret() failed");
+		return 1;
+	}
+	printf("Created memfd_secret (sec: %d): fd = %d\n", (int)_has_memfd_secret(), fd);
+
+	close(fd);
+	return 0;
+}