The following variables control the compiler command line:
     
- 
CPU_SOURCE 
 - The source CPU type is added as a define to the compiler command line.
     This is determined by the Makefile itself.
     
 - 
CPU_TARGET 
 - The target CPU type is added as a define to the compiler command line.
     This is determined by the Makefile itself.
     
 - 
OS_SOURCE 
 - What platform the makefile is used on. Detected automatically.
     
 - 
OS_TARGET 
 - What platform will be compiled for. Added to the compiler command line
     with a -T prepended.