regressions/ck_hp_fifo_donner: This was submitted from a Windows editor.

Switch to using UNIX EOL.
Add support for MinGW32.

This primarily involved changing the configure script and adding
several utility functions to regressions/common.h for unit testing.

Signed-off-by: Samy Al Bahra <sbahra@appnexus.com>
whitespace: Remove unnecessary newline.
build/configure: Add comment to test C program.