Segment the Yosemite brew install to be able to step back

[Peneheals]

Check for working curl, openss symlinks and versions.

Also check git and pkg-config.

Maybe also check, relocate and group temporary fixes (curlrc, symlinks, ssl verification).

• +1: check this with Yosemite and Mavericks: https://github.com/mistydemeo/tigerbrew

[Peneheals]

https://opensource.ncsa.illinois.edu/confluence/display/DESDM/Installing+pkg-config+from+source+for+OSX
https://gitlab.freedesktop.org/pkg-config/pkg-config