check the dependencies directory version

build/SConscript.configure

@@ -21,8 +21,11 @@ if not os.path.exists(configFile):
 	print 'A configuration file must be selected! Have a look at http://www.mitsuba-renderer.org/docs.html'
 	Exit(1)
 
-if (sys.platform == 'win32' or sys.platform == 'darwin') and not os.path.exists(GetBuildPath('#dependencies')):
-	print 'The dependencies are missing -- see http://www.mitsuba-renderer.org/devblog/archives/11-Build-system-changes.html'
+versionFilename = GetBuildPath('#dependencies/version')
+
+if not os.path.exists(versionFilename):
+	print 'The dependencies are missing -- please check out https://www.mitsuba-renderer.org/hg/dependencies'
+	print 'and ensure that the newly created directory is a subdirectory of the main Mitsuba folder'
 	Exit(1)
 
 # Parse configuration options
@@ -224,6 +227,18 @@ else:
 	print MTS_VERSION
 Export('MTS_VERSION')
 
+with open(versionFilename) as f:
+	depVersion = f.readline().strip()
+	if MTS_VERSION != depVersion:
+		print '\nThe dependency directory and your Mitsuba codebase have different version numbers!'
+		print 'Mitsuba has version %s, and the dependencies have version %s. Please bring them ' % (MTS_VERSION, depVersion)
+		print 'into sync, either by running \n'
+		print '$ hg update -r v%s\n' % depVersion 
+		print 'in the Mitsuba directory, or by running\n'
+		print '$ cd dependencies'
+		print '$ hg update -r v%s\n' % MTS_VERSION
+		Exit(1)
+
 env = conf.Finish()
 
 dist = GetOption('dist') != None