Fixes #2941 -- don't destroy extensionless filenames for --join

lib/coffee-script/helpers.js

@@ -167,7 +167,7 @@
     pathSep = useWinPathSep ? /\\|\// : /\//;
     parts = file.split(pathSep);
     file = parts[parts.length - 1];
-    if (!stripExt) {
+    if (!(stripExt && file.indexOf('.') >= 0)) {
       return file;
     }
     parts = file.split('.');

src/command.coffee

@@ -119,7 +119,7 @@ compilePath = (source, topLevel, base) ->
 # Compile a single source script, containing the given code, according to the
 # requested options. If evaluating the script directly sets `__filename`,
 # `__dirname` and `module.filename` to be correct relative to the script's path.
-compileScript = (file, input, base=null) ->
+compileScript = (file, input, base = null) ->
   o = opts
   options = compileOptions file, base
   try

src/helpers.coffee

@@ -122,7 +122,7 @@ exports.baseFileName = (file, stripExt = no, useWinPathSep = no) ->
   pathSep = if useWinPathSep then /\\|\// else /\//
   parts = file.split(pathSep)
   file = parts[parts.length - 1]
-  return file unless stripExt
+  return file unless stripExt and file.indexOf('.') >= 0
   parts = file.split('.')
   parts.pop()
   parts.pop() if parts[parts.length - 1] is 'coffee' and parts.length > 1