diff --git a/Makefile b/Makefile
index e91f2161..d18e4c0e 100644
--- a/Makefile
+++ b/Makefile
@@ -798,87 +798,4 @@ versions.json: $(foreach PKG,$(PKGS), $(TOP_DIR)/src/$(PKG).mk)
 
 # for patch-tool-mxe
 
-GIT_DIR = $(if $(patsubst .,,$($(1)_SUBDIR)) \
-    ,$(GITS_DIR)/$($(1)_SUBDIR),$(GITS_DIR)/$(1))
-
-GIT_CMD = git \
-    --work-tree='$(call GIT_DIR,$(1))' \
-    --git-dir='$(call GIT_DIR,$(1))'/.git
-
-define INIT_GIT
-    # unpack to gits/tmp/pkg
-    rm -rf '$(GITS_DIR)/tmp'
-    mkdir -p '$(GITS_DIR)/tmp/$(1)'
-    cd '$(GITS_DIR)/tmp/$(1)' && $(call UNPACK_PKG_ARCHIVE,$(1))
-    # if PKG_SUBDIR is ".", the following will move gits/tmp/pkg
-    mv '$(abspath $(GITS_DIR)/tmp/$(1)/$($(1)_SUBDIR))' '$(call GIT_DIR,$(1))'
-    rm -rf '$(GITS_DIR)/tmp'
-    # initialize git
-    $(call GIT_CMD,$(1)) init
-    $(call GIT_CMD,$(1)) add -A
-    $(call GIT_CMD,$(1)) commit -m "init"
-    $(call GIT_CMD,$(1)) tag dist
-endef
-
-init-git-%: download-only-%
-	$(if $(call set_is_member,$*,$(PKGS)), \
-	    $(if $(wildcard $(call GIT_DIR,$*)), \
-	        $(error $(call GIT_DIR,$*) already exists), \
-	        $(call INIT_GIT,$*)), \
-	    $(error Package $* not found in index.html))
-
-PATCH_NAME = 1-fixes
-
-# can't use PKG_PATCHES here, because it returns existing patches
-# while export-patch creates new patch
-PATCH_BY_NAME = $(patsubst %.mk,%-$(2).patch,$(PKG_MAKEFILES))
-
-define IMPORT_PATCH
-    cd '$(call GIT_DIR,$(1))' \
-        && cat '$(2)' \
-        | sed '/^From/,$$  !d' \
-        | sed s/'^From: MXE'/"From: fix@me"/'g;' \
-        | $(call GIT_CMD,$(1)) am --keep-cr ;
-endef
-
-import-patch-%:
-	$(if $(call set_is_member,$*,$(PKGS)), \
-	    $(if $(wildcard $(call GIT_DIR,$*)), \
-	        $(call IMPORT_PATCH,$*,$(call PATCH_BY_NAME,$*,$(PATCH_NAME))), \
-	        $(error $(call GIT_DIR,$*) does not exist)), \
-	    $(error Package $* not found in index.html))
-
-import-all-patches-%:
-	$(if $(call set_is_member,$*,$(PKGS)), \
-	    $(if $(wildcard $(call GIT_DIR,$*)), \
-	        $(foreach PKG_PATCH,$(call PKG_PATCHES,$*), \
-	            $(call IMPORT_PATCH,$*,$(PKG_PATCH))), \
-	        $(error $(call GIT_DIR,$*) does not exist)), \
-	    $(error Package $* not found in index.html))
-
-define EXPORT_PATCH
-    cd '$(call GIT_DIR,$(1))' \
-    && ( \
-        echo 'This file is part of MXE.'; \
-        echo 'See index.html for further information.'; \
-        echo ''; \
-        echo 'Contains ad hoc patches for cross building.'; \
-        echo ''; \
-        $(call GIT_CMD,$(1)) format-patch \
-            --no-numbered \
-            -p \
-            --no-signature \
-            --stdout \
-            --text \
-            dist..HEAD \
-        | sed 's/^From [0-9a-f]\{40\} /From 0000000000000000000000000000000000000000 /' \
-        | sed 's/^index .......\.\......../index 1111111..2222222/' \
-    ) > '$(PATCH_BY_NAME)'
-endef
-
-export-patch-%:
-	$(if $(call set_is_member,$*,$(PKGS)), \
-	    $(if $(wildcard $(call GIT_DIR,$*)), \
-	        $(call EXPORT_PATCH,$*,$(PATCH_NAME)), \
-	        $(error $(call GIT_DIR,$*) does not exist)), \
-	    $(error Package $* not found in index.html))
+include patch.mk
diff --git a/patch.mk b/patch.mk
new file mode 100644
index 00000000..87c72d00
--- /dev/null
+++ b/patch.mk
@@ -0,0 +1,87 @@
+# This file is part of MXE.
+# See index.html for further information.
+
+GIT_DIR = $(if $(patsubst .,,$($(1)_SUBDIR)) \
+    ,$(GITS_DIR)/$($(1)_SUBDIR),$(GITS_DIR)/$(1))
+
+GIT_CMD = git \
+    --work-tree='$(call GIT_DIR,$(1))' \
+    --git-dir='$(call GIT_DIR,$(1))'/.git
+
+PATCH_NAME = 1-fixes
+
+# can't use PKG_PATCHES here, because it returns existing patches
+# while export-patch creates new patch
+PATCH_BY_NAME = $(patsubst %.mk,%-$(2).patch,$(PKG_MAKEFILES))
+
+define INIT_GIT
+    # unpack to gits/tmp/pkg
+    rm -rf '$(GITS_DIR)/tmp'
+    mkdir -p '$(GITS_DIR)/tmp/$(1)'
+    cd '$(GITS_DIR)/tmp/$(1)' && $(call UNPACK_PKG_ARCHIVE,$(1))
+    # if PKG_SUBDIR is ".", the following will move gits/tmp/pkg
+    mv '$(abspath $(GITS_DIR)/tmp/$(1)/$($(1)_SUBDIR))' '$(call GIT_DIR,$(1))'
+    rm -rf '$(GITS_DIR)/tmp'
+    # initialize git
+    $(call GIT_CMD,$(1)) init
+    $(call GIT_CMD,$(1)) add -A
+    $(call GIT_CMD,$(1)) commit -m "init"
+    $(call GIT_CMD,$(1)) tag dist
+endef
+
+define IMPORT_PATCH
+    cd '$(call GIT_DIR,$(1))' \
+        && cat '$(2)' \
+        | sed '/^From/,$$  !d' \
+        | sed s/'^From: MXE'/"From: fix@me"/'g;' \
+        | $(call GIT_CMD,$(1)) am --keep-cr ;
+endef
+
+define EXPORT_PATCH
+    cd '$(call GIT_DIR,$(1))' \
+    && ( \
+        echo 'This file is part of MXE.'; \
+        echo 'See index.html for further information.'; \
+        echo ''; \
+        echo 'Contains ad hoc patches for cross building.'; \
+        echo ''; \
+        $(call GIT_CMD,$(1)) format-patch \
+            --no-numbered \
+            -p \
+            --no-signature \
+            --stdout \
+            --text \
+            dist..HEAD \
+        | sed 's/^From [0-9a-f]\{40\} /From 0000000000000000000000000000000000000000 /' \
+        | sed 's/^index .......\.\......../index 1111111..2222222/' \
+    ) > '$(PATCH_BY_NAME)'
+endef
+
+init-git-%: download-only-%
+	$(if $(call set_is_member,$*,$(PKGS)), \
+	    $(if $(wildcard $(call GIT_DIR,$*)), \
+	        $(error $(call GIT_DIR,$*) already exists), \
+	        $(call INIT_GIT,$*)), \
+	    $(error Package $* not found in index.html))
+
+import-patch-%:
+	$(if $(call set_is_member,$*,$(PKGS)), \
+	    $(if $(wildcard $(call GIT_DIR,$*)), \
+	        $(call IMPORT_PATCH,$*,$(call PATCH_BY_NAME,$*,$(PATCH_NAME))), \
+	        $(error $(call GIT_DIR,$*) does not exist)), \
+	    $(error Package $* not found in index.html))
+
+import-all-patches-%:
+	$(if $(call set_is_member,$*,$(PKGS)), \
+	    $(if $(wildcard $(call GIT_DIR,$*)), \
+	        $(foreach PKG_PATCH,$(call PKG_PATCHES,$*), \
+	            $(call IMPORT_PATCH,$*,$(PKG_PATCH))), \
+	        $(error $(call GIT_DIR,$*) does not exist)), \
+	    $(error Package $* not found in index.html))
+
+export-patch-%:
+	$(if $(call set_is_member,$*,$(PKGS)), \
+	    $(if $(wildcard $(call GIT_DIR,$*)), \
+	        $(call EXPORT_PATCH,$*,$(PATCH_NAME)), \
+	        $(error $(call GIT_DIR,$*) does not exist)), \
+	    $(error Package $* not found in index.html))
diff --git a/tools/build-pkg.lua b/tools/build-pkg.lua
index e9e7287d..7cd853f1 100755
--- a/tools/build-pkg.lua
+++ b/tools/build-pkg.lua
@@ -800,6 +800,7 @@ local function makeMxeSourcePackage()
         'CNAME',
         'LICENSE.md',
         'Makefile',
+        'patch.mk',
         'README.md',
         'assets',
         'doc',