updated for version 7.4.476
Problem:    MingW: compiling with "XPM=no" doesn't work.
Solution:   Check for the "no" value. (KF Leong)  Also for Cygwin. (Ken
            Takata)
diff --git a/src/Make_cyg.mak b/src/Make_cyg.mak
index 4b9985f..abd35a6 100644
--- a/src/Make_cyg.mak
+++ b/src/Make_cyg.mak
@@ -485,7 +485,7 @@
 endif
 
 ##############################
-ifdef XPM
+ifneq ($(XPM),no)
 # Only allow XPM for a GUI build.
 DEFINES += -DFEAT_XPM_W32
 INCLUDES += -I$(XPM)/include