Making tcmalloc the default when compatible with host compiler
Using target compiler instead of host compiler
Simplifying logic
Ensure ~/.bashrc exists before sourcing it.
Merge pull request #321 from thomasvandoren/robustify-nightly-common

Ensure ~/.bashrc exists before sourcing it.

Robustify `util/cron/common.bash` in the case that ~/.bashrc does not exist.
Not using tcmalloc on cygwin, for now
Merge pull request #320 from benharsh/tcmalloc

This small script change makes tcmalloc the default allocator for compatible compilers: gnu, intel, and clang.

For now, tcmalloc will not be the default for cygwin.
Add new test scripts for new mac testing machine.
Merge pull request #322 from thomasvandoren/new-mac-testing

Add new test scripts for new mac testing machine.