fix to allow mingw+vpath

The simple change below allows a vpath build to be used on Mingw. Is
there any objection?

cheers

andrew

diff --git a/src/bin/pgevent/Makefile b/src/bin/pgevent/Makefile
index 013b801..39cb7dc 100644
--- a/src/bin/pgevent/Makefile
+++ b/src/bin/pgevent/Makefile
@@ -27,7 +27,7 @@ pgevent.dll: pgevent.def $(OBJS)
     $(DLLWRAP) --def $< -o $(NAME) $(OBJS)

  pgmsgevent.o: pgmsgevent.rc win32ver.rc
-   $(WINDRES) $< -o $@ --include-dir=$(top_builddir)/src/include 
--include-dir=$(top_srcdir)/src/include --include-dir=$(srcdir)
+   $(WINDRES) $< -o $@ --include-dir=$(top_builddir)/src/include 
--include-dir=$(top_srcdir)/src/include --include-dir=$(srcdir) 
--include-dir=.

all-lib: $(NAME)