Filter the --enable-static/--disable-shared flags only for Cray platforms
Filter the --enable-static/--disable-shared flags only for Cray platforms

This should make the C compile-time warning go away for Mac while
avoding building the .so's on Crays.  It's also most similar to what
we've been testing by default for the past several months.

CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,hildeth/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,CoryMcCartan/chapel,hildeth/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel