Yeah, malloc(), free(), etc are ported straight from C.
So you wont find much mention in the 3DGS helpfiles about them.
Use any old C, C++ documentation for usage.

They are included by the "LiteC.h" header or you can #include the "malloc.h" that comes bundled with A7.
Well, it was bundled with my A7 commercial version anyway. Dont know about Free Lite-C....