Bad behavior for misspelled CC or CXX

[Paul Hargrove]

For configure --with=cxx=nope the current behavior in system-checks.sh is to set CXX to an empty string and the default is used! Additionally --with-cxx='nope -m64' sets CXX=' -m64', which at least results in GASNet's configure dying quickly.

The problem is rooted in how type -p is applied to discover the fullpath.
So, the problem was present with the nobs infrastructure too and this is not a regression relative to prior releases.

[Paul Hargrove]

Proposed solution in pull request 158

[Paul Hargrove]

Check that CC and CXX exist

This commit resolves issue 304 (Bad behavior for misspelled CC or CXX) by introducing an intermediate step in the absification of the compilers, allowing for detection of empty results from type -p ....

→ <<cset 8bc0a575ad89>>