added Help text (scons -h) and a option to pass CC

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-merge-1.4.x@957 152afb58-edef-0310-8abb-c4023f1b3aa9

SConstruct

@@ -81,6 +81,7 @@ opts.AddOptions(
 	PackageOption('with_mysql', 'enable mysql support', 'no'),
 	PackageOption('with_xml', 'enable xml support', 'no'),
 	PackageOption('with_pcre', 'enable pcre support', 'yes'),
+	PathOption('CC', 'path to the c-compiler', None),
 	BoolOption('build_dynamic', 'enable dynamic build', 'yes'),
 	BoolOption('build_static', 'enable static build', 'no'),
 	BoolOption('build_fullstatic', 'enable fullstatic build', 'no'),
@@ -99,6 +100,11 @@ env = Environment(
 	CPPPATH = Split('#/build')
 )
 
+env.Help(opts.GenerateHelpText(env))
+
+if env.subst('${CC}') is not '':
+	env['CC'] = env.subst('${CC}')
+
 env['package'] = package
 env['version'] = version
 if env['CC'] == 'gcc':