C++ headers generated by Java API generator for a full JDK or Android library typically contain tens of thousands SCAPIX_META_STRING expressions - one for each method/field of each java class and interface. This can significantly slow down compilation.
Implementation of SCAPIX_META_STRING contains optimization using non-standard C++ extension supported by clang and gcc compilers. Enable non-standard C++ extensions to speedup compilation of generated headers using clang and gcc:
set_target_properties(<TargetName> PROPERTIES CXX_STANDARD 17 CXX_STANDARD_REQUIRED ON CXX_EXTENSIONS ON )