Support Trusty, an embedded platform.

Trusty doesn't have setjmp.h and nor does it have threads.

Change-Id: I005f7a009a13e6632513be9fab2bbe62294519a4
Reviewed-on: https://boringssl-review.googlesource.com/4660
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/thread_test.c b/crypto/thread_test.c
index 04d71c5..cecda88 100644
--- a/crypto/thread_test.c
+++ b/crypto/thread_test.c
@@ -17,6 +17,8 @@
 #include <stdio.h>
 
 
+#if !defined(OPENSSL_NO_THREADS)
+
 #if defined(OPENSSL_WINDOWS)
 
 #pragma warning(push, 3)
@@ -189,3 +191,12 @@
   printf("PASS\n");
   return 0;
 }
+
+#else  /* OPENSSL_NO_THREADS */
+
+int main(int argc, char **argv) {
+  printf("PASS\n");
+  return 0;
+}
+
+#endif