Bypass building fipsmodule/rand/urandom.c when builing for Trusty

Change-Id: Icf1d6ec9d3fb33a124a9f61c75d29248a2582680
Reviewed-on: https://boringssl-review.googlesource.com/15964
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/crypto/fipsmodule/rand/urandom.c b/crypto/fipsmodule/rand/urandom.c
index 7f76145..202f2a4 100644
--- a/crypto/fipsmodule/rand/urandom.c
+++ b/crypto/fipsmodule/rand/urandom.c
@@ -15,7 +15,7 @@
 #include <openssl/rand.h>
 
 #if !defined(OPENSSL_WINDOWS) && !defined(OPENSSL_FUCHSIA) && \
-    !defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE)
+    !defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE) && !defined(OPENSSL_TRUSTY)
 
 #include <assert.h>
 #include <errno.h>
@@ -291,4 +291,4 @@
 }
 
 #endif /* !OPENSSL_WINDOWS && !defined(OPENSSL_FUCHSIA) && \
-          !BORINGSSL_UNSAFE_DETERMINISTIC_MODE */
+          !BORINGSSL_UNSAFE_DETERMINISTIC_MODE && !OPENSSL_TRUSTY */