Fixing ports to build without the command line tools

[Ryan Schmidt]

In this commit message:

https://github.com/macports/macports-base/commit/2eac8d6a35dce2ca2e7eeaa5848933b5c57498cd

Jeremy wrote, regarding MacPorts warning when the command line tools are not installed:

> We should probably not be warning about this at all.  Most ports should build fine without the CLTools, and we should fix cases where they do not.

graphite2 is an example of a port that fails to build when the command line tools are not installed:

https://trac.macports.org/ticket/49325

How would we go about fixing such problems?