Uncommented a line in the FREE_WINDOWS section that appears to control the

detection of changes to dependencies. This should resolve issues with
Cygwin builds using makefiles which have bizarre behavior if 'make clean'
was not used before compile.

source/nan_compile.mk

@@ -189,7 +189,7 @@ ifeq ($(OS),windows)
     CPPFLAGS += -DFREE_WINDOWS
     REL_CFLAGS += -O2
     REL_CCFLAGS += -O2
-    #NAN_DEPEND = true
+    NAN_DEPEND = true
     #OPENGL_HEADERS = /usr/include/w32api
     OPENGL_HEADERS = ./
     AR = ar