Changeset 7461924 in rtems-tools for linkers/rld-cc.h

Rename rld-gcc. Add -C option.

Add a -C (also --cc) option to allow the CC to be used when linking to be
provided by the user rather than using the path. This support allows user
who work with the full path to tools rather than the environment to make
use of the linker without them needing to play with environment table.

Rename rld-gcc.[h.cpp] to rld-cc.[h,cpp] because gcc may not be the
only compiler/linker used by the RTEMS project.