Maike ES6 Module

This makes an ES6 Module for SqlJs, not sure how it affects the other generated files. Based on Roy's comment sql-js#438 (comment)

import initSqlJs from 'URL TO /sql-wasm.mjs';
const SQL =  await initSqlJs({
  // Required to load the wasm binary asynchronously. Of course, you can host it wherever you want
  // You can omit locateFile completely when running in node
  locateFile: file => `URL TO /sql-wasm.wasm`
});

Author: twoxfh

Makefile

@@ -38,7 +38,8 @@ EMFLAGS = \
 	-s EXPORTED_RUNTIME_METHODS=@src/exported_runtime_methods.json \
 	-s SINGLE_FILE=0 \
 	-s NODEJS_CATCH_EXIT=0 \
-	-s NODEJS_CATCH_REJECTION=0
+	-s NODEJS_CATCH_REJECTION=0 \
+	-s MODULARIZE=1
 
 EMFLAGS_ASM = \
 	-s WASM=0
@@ -91,7 +92,7 @@ dist/sql-wasm-debug.js: $(BITCODE_FILES) $(OUTPUT_WRAPPER_FILES) $(SOURCE_API_FI
 	rm out/tmp-raw.js
 
 .PHONY: optimized
-optimized: dist/sql-asm.js dist/sql-wasm.js dist/sql-asm-memory-growth.js
+optimized: dist/sql-asm.js dist/sql-wasm.js dist/sql-wasm.mjs dist/sql-asm-memory-growth.js
 
 dist/sql-asm.js: $(BITCODE_FILES) $(OUTPUT_WRAPPER_FILES) $(SOURCE_API_FILES) $(EXPORTED_METHODS_JSON_FILES)
 	$(EMCC) $(EMFLAGS) $(EMFLAGS_OPTIMIZED) $(EMFLAGS_ASM) $(BITCODE_FILES) $(EMFLAGS_PRE_JS_FILES) -o $@
@@ -105,6 +106,9 @@ dist/sql-wasm.js: $(BITCODE_FILES) $(OUTPUT_WRAPPER_FILES) $(SOURCE_API_FILES) $
 	cat src/shell-pre.js out/tmp-raw.js src/shell-post.js > $@
 	rm out/tmp-raw.js
 
+dist/sql-wasm.mjs: $(BITCODE_FILES) $(SOURCE_API_FILES) $(EXPORTED_METHODS_JSON_FILES)
+	$(EMCC) $(EMFLAGS) $(EMFLAGS_OPTIMIZED) $(EMFLAGS_WASM) $(BITCODE_FILES) $(EMFLAGS_PRE_JS_FILES) -o $@
+
 dist/sql-asm-memory-growth.js: $(BITCODE_FILES) $(OUTPUT_WRAPPER_FILES) $(SOURCE_API_FILES) $(EXPORTED_METHODS_JSON_FILES)
 	$(EMCC) $(EMFLAGS) $(EMFLAGS_OPTIMIZED) $(EMFLAGS_ASM_MEMORY_GROWTH) $(BITCODE_FILES) $(EMFLAGS_PRE_JS_FILES) -o $@
 	mv $@ out/tmp-raw.js