diff --git a/crypto/modes/gcm_test.cc b/crypto/modes/gcm_test.cc
index 8fee4e4..8baf20e 100644
--- a/crypto/modes/gcm_test.cc
+++ b/crypto/modes/gcm_test.cc
@@ -46,6 +46,13 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  * ==================================================================== */
 
+/* Per C99, various stdint.h and inttypes.h macros (the latter used by
+ * internal.h) are unavailable in C++ unless some macros are defined. C++11
+ * overruled this decision, but older Android NDKs still require it. */
+#if !defined(__STDC_CONSTANT_MACROS)
+#define __STDC_CONSTANT_MACROS
+#endif
+
 #include <stdio.h>
 #include <string.h>