Move the Modula-2 library includes into a directory in lang/m2 where they belong.

lang/m2/comp/build.lua

@@ -111,6 +111,7 @@ cprogram {
 		"+real_h",
 		"+type_h",
 		"h+emheaders",
+		"lang/m2/include+headers",
 		"modules+headers",
 		"modules/src/alloc+lib",
 		"modules/src/data+lib",

lang/m2/include/build.lua

@@ -0,0 +1,4 @@
+clibrary {
+	name = "headers",
+	hdrs = {"./*.h"}
+}

lang/m2/libm2/build.lua

@@ -32,6 +32,7 @@ for _, plat in ipairs(vars.plats) do
 			"lang/cem/libcc.ansi/headers+pkg",
 			"plat/"..plat.."/include+pkg",
 			"h+emheaders",
+			"lang/m2/include+headers",
 		},
         vars = { plat = plat }
     }