Add executable suffix for the tool. This is needed e.g. for 'make install' on mingw32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78185 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile.rules b/Makefile.rules
index 6fe6868..5a5544c 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -1212,7 +1212,7 @@
 uninstall-local::
 	$(Echo) Uninstall circumvented with NO_INSTALL
 else
-DestTool = $(PROJ_bindir)/$(TOOLNAME)
+DestTool = $(PROJ_bindir)/$(TOOLNAME)$(EXEEXT)
 
 install-local:: $(DestTool)