android: Switch to CLOCK_REALTIME on Android

This allows measuring the delay between events more accurately if a
device is often suspended.

While CLOCK_BOOTTIME would be preferable, Android's bionic C library
does not support it for condvars.

src/libstrongswan/utils/compat/android.h

@@ -37,6 +37,9 @@
 #define HAVE_PTHREAD_CONDATTR_INIT 1
 #define HAVE_CONDATTR_CLOCK_MONOTONIC 1
 
+#undef TIME_CLOCK_ID
+#define TIME_CLOCK_ID CLOCK_REALTIME
+
 #define HAVE_SYS_CAPABILITY_H 1
 
 #else /* __ANDROID_API__ */