Fix anonymous class error

Fail to compile bionic/tests/complex_test.cpp when updating compiler due
to the conflict.

Bug: b/346349678
Test: change the clang version and then run mm to build
Change-Id: Ic22b7325b6e52006e620e13944f3f1d76030d782
diff --git a/tests/complex_test.cpp b/tests/complex_test.cpp
index 6a1831f..8fdb2b2 100644
--- a/tests/complex_test.cpp
+++ b/tests/complex_test.cpp
@@ -32,7 +32,11 @@
 #include <math.h> // For M_PI_2/M_PI_2l.
 
 // Prettify gtest Complex printing.
+// Macro 'complex' defined in complex.h conflicts with iostream.
+#pragma push_macro("complex")
+#undef complex
 #include <iostream>
+#pragma pop_macro("complex")
 namespace testing {
 namespace internal {
 inline void PrintTo(const double _Complex& c, std::ostream* os) {