patch 8.1.0084: user name completion does not work on MS-Windows

Problem:    User name completion does not work on MS-Windows.
Solution:   Use NetUserEnum() to get user names. (Yasuhiro Matsumoto)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index d51b6ea..cdec101 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -662,7 +662,7 @@
 CFLAGS += -s
 endif
 
-LIB = -lkernel32 -luser32 -lgdi32 -ladvapi32 -lcomdlg32 -lcomctl32 -lversion
+LIB = -lkernel32 -luser32 -lgdi32 -ladvapi32 -lcomdlg32 -lcomctl32 -lnetapi32 -lversion
 GUIOBJ =  $(OUTDIR)/gui.o $(OUTDIR)/gui_w32.o $(OUTDIR)/gui_beval.o $(OUTDIR)/os_w32exe.o
 CUIOBJ = $(OUTDIR)/iscygpty.o
 OBJ = \