Add missing stdbool include for C compat.

Bug: android/ndk#1920
Test: clang --sysroot out/soong/ndk/sysroot
          out/soong/ndk/sysroot/usr/include/**/*.h

Change-Id: Ic93ef129ae3c2014435699dcdca56215bdb00d59

Author: Dan Albert

include/android/performance_hint.h

@@ -53,6 +53,7 @@
  */
 
 #include <android/api-level.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <unistd.h>