Move the compiler-selecting methods to ENV/shared

Closes #30210.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
Use Pathname#split
Use a more descriptive variable name
osh: V6 Thompson Shell Port
osh: add 20140410 bottle.

Closes #30123.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Remove obsolete constant

Formula that use this do not load anymore.