[c86] Modify ecc compiler driver script to run directly on ELKS

[ghaerr]

Updates ecc to allow directly running on ELKS. This now allows the same script to run the C86 compiler driver from a cross-compilation host environment or on ELKS itself.

Unfortunately, cpp86 seems to be running into trouble when passed the -D flags required for compiling the library, etc. This will have to be fixed before we can proceed much further. I suspect the problem is related to CPP86 either not having enough heap space, or possibly having to use fmemalloc etc. It could also be related to make either having too much heap or being too large to allow other C86 programs to run. Not sure yet.

I am instead going to work on getting ELKS make to work, where it is also running into more problems with the tools running out of memory (in this case NASM afterwards). Using a Makefile, I as able to remove the CPP86 -D options so at least it would continue for the time being.

I will open a PR on 8086-toolchain showing the continued problems for @rafael2k's testing and tools debugging of CPP86 and/or NASM.

Here's a screen shot showing the problem (the system crashes afterwards):