Fix a bug where the value of ${SOMEVAR} would simply disappear if there was a separator character immediately before it.  This wasn't likely to happen in #-lines, but we might as well get it right.  Also fix it so that "" and "" will create a zero-length argument.
Fix a bug where the value of ${SOMEVAR} would simply disappear if there
was a separator character immediately before it.  This wasn't likely to
happen in #-lines, but we might as well get it right.  Also fix it so
that "" and "" will create a zero-length argument.

Approved by:	re (blanket `env')

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase