Add LibreJS license tag

Makefile

@@ -191,6 +191,9 @@ wasm: $(WASM_TARGET)
 $(WASM_TARGET): $(WASM_OBJECTS)
 	$(EMAR) rcs $@ $^
 
+javascript/olm_prefix.js: javascript/olm_prefix.js.in Makefile
+	sed s/@VERSION@/$(VERSION)/ javascript/olm_prefix.js.in > $@
+
 # Note that the output file we give to emcc determines the name of the
 # wasm file baked into the js, hence messing around outputting to olm.js
 # and then renaming it.

javascript/olm_prefix.js → javascript/olm_prefix.js.in

+// @license magnet:?xt=urn:btih:8e4f440f4c65981c5bf93c76d35135ba5064d8b7&dn=apache-2.0.txt Apache-2.0
+// @source: https://gitlab.matrix.org/matrix-org/olm/-/tree/@VERSION@
+
 var Olm = (function() {
 var olm_exports = {};
 var onInitSuccess;

javascript/olm_suffix.js

@@ -34,3 +34,5 @@ if (typeof module === 'object') {
     // level wrapper class.
     module.exports = Olm;
 }
+
+// @license-end