Add more __BIONIC_AVAILABILITY_GUARD().

Bug: None
Test: treehugger
Change-Id: I9f4c85135220021aaee4d5d047844de29526e93b
diff --git a/tests/complex_test.cpp b/tests/complex_test.cpp
index 8fdb2b2..ed0109a 100644
--- a/tests/complex_test.cpp
+++ b/tests/complex_test.cpp
@@ -20,6 +20,9 @@
 #if !defined(__INTRODUCED_IN)
 #define __INTRODUCED_IN(x)
 #endif
+#if !defined(__BIONIC_AVAILABILITY_GUARD)
+#define __BIONIC_AVAILABILITY_GUARD(x) 1
+#endif
 
 // libc++ actively gets in the way of including <complex.h> from C++, so we
 // have to be naughty.