* Src/Lexer/AbstractLexer.cs: Added null check.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/3.0@3867 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Libraries/NRefactory/Project/Src/Lexer/AbstractLexer.cs

@@ -48,6 +48,7 @@ namespace ICSharpCode.NRefactory.Parser
 		
 		protected static IEnumerable<string> GetSymbols (string symbols)
 		{
+			if (!string.IsNullOrEmpty(symbols)) {
 				foreach (string symbol in symbols.Split (';')) {
 					string s = symbol.Trim ();
 					if (s.Length == 0)
@@ -55,6 +56,7 @@ namespace ICSharpCode.NRefactory.Parser
 					yield return s;
 				}
 			}
+		}
 		
 		public virtual void SetConditionalCompilationSymbols (string symbols)
 		{