sub makefiles: standardize names and add to build-pkg

Makefile

@@ -215,7 +215,7 @@ define AUTOTOOLS_BUILD
 endef
 
 # include github related functions
-include $(PWD)/github.mk
+include $(PWD)/mxe.github.mk
 
 # shared lib preload to disable networking, enable faketime etc
 PRELOAD_VARS := LD_PRELOAD DYLD_FORCE_FLAT_NAMESPACE DYLD_INSERT_LIBRARIES
@@ -1081,5 +1081,5 @@ docs/packages.json: $(foreach 1,$(PKGS),$(PKG_MAKEFILES))
 	@echo '}'                        >> $@
 
 # for other mxe functions
-include patch.mk
+include mxe.patch.mk
-include updates.mk
+include mxe.updates.mk

tools/build-pkg.lua

@@ -1057,14 +1057,16 @@ local function makeMxeSourcePackage()
     -- dependencies
     local deps = {}
     local files = {
+        'docs',
+        'ext',
         'LICENSE.md',
         'Makefile',
-        'patch.mk',
+        'mxe.github.mk',
+        'mxe.patch.mk',
+        'mxe.updates.mk',
+        'plugins',
         'README.md',
-        'docs',
-        'ext',
         'src',
-        'plugins',
         'tools',
     }
     local d1 = "MXE source"