Rename files, delete old windows makefiles

plugins/checksum/makefile.mak

@@ -1,18 +0,0 @@
-include "..\..\src\makeinc.mak"
-
-all: checksum.obj checksum.def
-	link $(LDFLAGS) $(LIBS) /dll /out:xcchecksum.dll /def:checksum.def checksum.obj 
-
-checksum.def:
-	echo EXPORTS > checksum.def
-	echo xchat_plugin_init >> checksum.def
-	echo xchat_plugin_deinit >> checksum.def
-
-checksum.obj: checksum.c makefile.mak
-	cl $(CFLAGS) /I.. checksum.c
-
-clean:
-	del *.obj
-	del *.dll
-	del *.exp
-	del *.lib