[libc] Fix glitch when building elks-libc on launchpad.net

[tkchia]

No description provided.

[ghaerr]

Hello @tkchia,

LGTM. Out of curiosity - why is the ~ problem turning up only on launchpad.net?

Thank you!

[tkchia]

Hello @ghaerr,

On launchpad.net the ELKS libc code was being built inside a build directory with a ~ inside the path component due to a pre-release "version number", something like (IIRC) elks-libc-gcc-ia16-elf-0.8.0~pre-dev. The issue did not occur on e.g. my local PC, because I was not building ELKS libc in a directory with a ~ in its name.

Thank you!