Remove -include <file> when compiling stubs.

Otherwise, the force included headers might cause conflicting types
error with the symbols in the generated stubs source code. e.g.

double acos(double); // in header
void acos() {} // in the generated source code

Bug: 120266448
Test: m (apex_test also updated, and passing)
Change-Id: I717df990959d1b24ec515f0f52a4e28b94e92f32