diff --git a/build/core/pathmap.mk b/build/core/pathmap.mk
new file mode 100644
index 0000000..39a2b06
--- /dev/null
+++ b/build/core/pathmap.mk
@@ -0,0 +1,40 @@
+#
+# Returns the path to the requested module's include directory,
+# relative to the root of the source tree.  Does not handle external
+# modules.
+#
+# $(1): a list of modules (or other named entities) to find the includes for
+#
+define include-path-for
+$(foreach n,$(1),$(patsubst $(n):%,%,$(filter $(n):%,$(pathmap_INCL))))
+endef
+
+# Enter project path into pathmap
+#
+# $(1): name
+# $(2): path
+#
+define project-set-path
+$(eval pathmap_PROJ += $(1):$(2))
+endef
+
+# Enter variant project path into pathmap
+#
+# $(1): name
+# $(2): variable to check
+# $(3): base path
+#
+define project-set-path-variant
+    $(call project-set-path,$(1),$(strip \
+        $(if $($(2)), \
+            $(3)-$($(2)), \
+            $(3))))
+endef
+
+# Returns the path to the requested module's include directory,
+# relative to the root of the source tree.
+#
+# $(1): a list of modules (or other named entities) to find the projects for
+define project-path-for
+$(foreach n,$(1),$(patsubst $(n):%,%,$(filter $(n):%,$(pathmap_PROJ))))
+endef