msh: use list_memheap when RT_USING_MEMHEAP_AS_HEAP is enabled

There is no list_mem and only list_memheap when RT_USING_MEMHEAP_AS_HEAP
is enabled.
module: add !__CC_ARM when test __GNUC__

ARMCC will define __GNUC__ in "GNU mode"(with --gnu command line
option). So iff __GNUC__ && !__CC_ARM is GCC.
Merge pull request #389 from grissiom/misc-fix

Misc fix