EXEEXT inconsistently added

[Tim Van Holder]

libtool's pdemo has

bin_PROGRAMS = hell hell.static helldl

hell.static stays that way in Makefile, but a rule
is generated for hell.static$(EXEEXT) (like it should).
If $(EXEEXT) is set, it should be appended to all
bin_PROGRAMS, regardless of any existing extension.
Alternatively, the rule should be generated for
'hell.static', but since hell.static.exe would probably
still be created instead of hell.static, that could lead
to dependency problems.