MAKEALL: Fix return value

Previously MAKEALL would always return a value of 0, even if 1 or more
boards did not compile.  This change causes MAKEALL to return 0 if all
boards were able to build, otherwise 1.

This change also requires changing the script interpreter from sh to
bash to support bash's PIPESTATUS variable.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>