Sorry if this isn't the correct place to post this, but I couldn't find a better location.
I have a program that I want to be compiled from either the CLI or the on-line compiler (via mbed.com). But some of the code that is pulled in by the CLI tools (GCC_ARM) isn't available when using the on-line compiler, so I was looking for a define that indicates that the compiler being used is uniquely the "on-line compiler'
Is there such a define/flag that I can test in the code to conditionally include code? Basically,

#ifdef online_compiler
do this...
#else
do that...
#endif