diff --git a/src/Makefile.global.in b/src/Makefile.global.in
index bb732bb..b562378 100644
--- a/src/Makefile.global.in
+++ b/src/Makefile.global.in
@@ -422,7 +422,11 @@ ifndef PGXS
  submake-libpq:
     $(MAKE) -C $(libpq_builddir) all
  else
-submake-libpq: $(libdir)/libpq.so ;
+ifneq ($(PORTNAME),cygwin)
+submake-libpq: $(libdir)/libpq$(DLSUFFIX) ;
+else
+submake-libpq: $(libdir)/cygpq$(DLSUFFIX) ;
+endif
  endif

  ifndef PGXS