mcrun tool enhancement wishlist

[willend]

It would be nice with these additions / improved features for mcrun / mxrun:

• Honouring CFLAGS and LDFLAGS from surrounding environment
• A commandline-switch for further CFLAGS, e.g. --CFLAGS="enable some profiling/debugging feature" that would add to CFLAGS (the thinking is here that these are added, not replacing the configuration-settings read from the toolchain json file
• A commandline-switch --dprefix that can be used to define a directory pattern to be used together with a time-stamp (default behaviour is to use the instrument name, this would replace the instrument name in the directory)