fix broken logic for oshmem:bindings:fort
Refs #3763
Portability fix: better checking for MAP_ANONYMOUS and MAP_ANON.

Thanks to Paul Hargrove for identifying the issue and suggesting the
fix.
Don't instantiate+init variables in a switch block.
    
Avoid compiler warning about (unnecessarily) initializing 2 variables
during instantiation at the top of a switch block (but outside of any
case statements): just declare the variables at the top of the outter
block.  They're already safely initialized, so don't worry about
initializing them in the instantiation.

Reviewed by Dave Goodell.

cmr=v1.7.4:reviewer=ompi-rm1.7:subject=Don't instantiate+init variables in a switch block