root Specifies root directory of the compiler installation. This option is necessary only if it is not possible to detect this information from the compiler command—for example if the specified compiler command is a user script.

cflags Specifies additional compiler flags that will be used when compiling C sources. cxxflags Specifies additional compiler flags that will be used when compiling C++ sources. compileflags Specifies additional compiler flags that will be used when compiling both C and C++ sources. linkflags Specifies additional command line options that will be passed to the linker.