spindle-build not handling --prefix=path properly for path strings that contain macros which get expanded by CPP

[mcfadden8]

This is discussed some in pull request #9.

I discovered yesterday that when I used prefix=/foo/bar/linux-rhel7 for configure, the C preprocessor was expanding that to "/foo/bar/1-rhel7". This is because "linux" was itself a macro which expanded to "1" in the code when $SRC/src/logging/spindle_logc.c was pre-processed.

[mplegendre]

Fixed.