Include <assert.h> for static_assert in C11.

Bug: https://github.com/android-ndk/ndk/issues/511
Test: builds
Change-Id: I67aba75343c3f40f7beb592bc30f34f5422f6f27

media/ndk/include/media/NdkMediaCodec.h

@@ -149,6 +149,7 @@ ssize_t AMediaCodec_dequeueInputBuffer(AMediaCodec*, int64_t timeoutUs);
 
 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
     __STDC_VERSION__ >= 201112L
+#include <assert.h>
 static_assert(sizeof(_off_t_compat) == sizeof(long),
               "_off_t_compat does not match the NDK ABI. See "
               "https://github.com/android-ndk/ndk/issues/459.");