Variable assignment and wildcarding not working for file names containing a period

[ScottA678]

Implementing feature delivered in #344 and #343

I have set up rules to implement a global value for TGTRLS:
PROJECT_TGTRLS := *PRV
%.MODULE: private TGTRLS := $(PROJECT_TGTRLS)

On a V7R4 system the following recipe resolves to TGTRLS():
AB2001.B.MODULE: AB2001.B.RPGLE

The following recipe resolves to TGTRLS(*PRV):
AB2001_B.MODULE: AB2001_B.RPGLE

The only difference I can see is the name of the file.