Back out incomplete ESM support for 3.0.0

This is incomplete, and it looks like we might just switch to
only generating ES6 code with ESM modules.  We need to resolve how
the JS demo on the website is built first though.

Author: ojwb

GNUmakefile

@@ -332,7 +332,7 @@ $(go_src_dir)/%_stemmer.go: algorithms/%.sbl snowball$(EXEEXT)
 
 $(js_output_dir)/%-stemmer.js: algorithms/%.sbl snowball$(EXEEXT)
 	@mkdir -p $(js_output_dir)
-	./snowball $< -js="$(JSTYPE)" -o "$(js_output_dir)/$*-stemmer"
+	./snowball $< -js -o "$(js_output_dir)/$*-stemmer"
 
 $(js_output_dir)/base-stemmer.js: $(js_runtime_dir)/base-stemmer.js
 	@mkdir -p $(js_output_dir)

NEWS

@@ -178,8 +178,6 @@ Javascript
     `/usr/bin/nodejs` because `/usr/bin/node` was already in use by a
     completely different package, but that has since changed).
 
-  + Add start of ESM support.  See #183, reported by Lionel Rowe.
-
 Pascal
 ------
 

compiler/driver.c

@@ -28,10 +28,6 @@ static int eq(const char * s1, const char * s2) {
     return strcmp(s1, s2) == 0;
 }
 
-static int startswith(const char * s1, const char * s2) {
-    return strncmp(s1, s2, strlen(s2)) == 0;
-}
-
 static void print_arglist(int exit_code) {
     FILE * f = exit_code ? stderr : stdout;
     fprintf(f, "Usage: snowball SOURCE_FILE... [OPTIONS]\n\n"
@@ -53,8 +49,7 @@ static void print_arglist(int exit_code) {
                "  -py, -python\n"
 #endif
 #ifndef DISABLE_JS
-               "  -js[=TYPE]                       generate Javascript (TYPE values:\n"
-               "                                   esm global, default: global)\n"
+               "  -js                              generate Javascript\n"
 #endif
 #ifndef DISABLE_RUST
                "  -rust\n"
@@ -170,17 +165,6 @@ static int read_options(struct options * o, int argc, char * argv[]) {
                 o->js_esm = false;
                 continue;
             }
-            if (startswith(s, "-js=")) {
-                o->make_lang = LANG_JAVASCRIPT;
-                if (eq(s + 4, "global")) {
-                    o->js_esm = false;
-                } else if (eq(s + 4, "esm")) {
-                    o->js_esm = true;
-                } else {
-                    fprintf(stderr, "Unknown Javascript type '%s'\n", s + 4);
-                }
-                continue;
-            }
 #endif
 #ifndef DISABLE_RUST
             if (eq(s, "-rust")) {