Use a Python script to generate requireall.js

This is needed to work around platform variations in the sort command.

Makefile

@@ -36,9 +36,9 @@ build/src/external/externs/types.js: bin/generate-src src/ol/literals.txt
 	mkdir -p $(dir $@)
 	bin/generate-src --externs src/ol/literals.txt >$@
 
-build/src/internal/src/requireall.js: $(SRC)
+build/src/internal/src/requireall.js: bin/generate-requireall $(SRC)
 	mkdir -p $(dir $@)
-	( echo "goog.require('goog.dom');" ; find src/ol -name \*.js | xargs grep -rh ^goog.provide | sort | uniq | sed -e 's/provide/require/g' ) >$@
+	bin/generate-requireall --require=goog.dom src/ol >$@
 
 build/src/internal/src/types.js: bin/generate-src src/ol/literals.txt
 	mkdir -p $(dir $@)

bin/generate-requireall

@@ -0,0 +1,32 @@
+#!/usr/bin/env python
+
+from optparse import OptionParser
+import os
+import os.path
+import re
+import sys
+
+
+def main(argv):
+
+    option_parser = OptionParser()
+    option_parser.add_option('--require', action='append')
+    options, args = option_parser.parse_args(argv[1:])
+
+    requires = set(options.require or ())
+    for arg in args:
+        for dirpath, dirnames, filenames in os.walk(arg):
+            for filename in filenames:
+                if not filename.endswith('.js'):
+                    continue
+                for line in open(os.path.join(dirpath, filename)):
+                    m = re.match(r'goog\.provide\(\'(.*)\'\);', line)
+                    if m:
+                        requires.add(m.group(1))
+
+    for require in sorted(requires):
+        sys.stdout.write('goog.require(\'%s\');\n' % (require,))
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))