[patch] bug 2468: LyX doesn't take care of document language changes

[Jürgen Spitzmüller]

http://bugzilla.lyx.org/show_bug.cgi?id=2468

This is another easyfix I have in my tree for some time. It's straighforward, 
harmless and well tested, so I'm gonna commit to branch and trunk.

Jürgen

Index: src/LaTeX.cpp
===================================================================
--- src/LaTeX.cpp	(Revision 19199)
+++ src/LaTeX.cpp	(Arbeitskopie)
@@ -689,7 +689,9 @@
 				// we have a latex error
 				retval |=  TEX_ERROR;
 				if (contains(desc,
-				    "Package babel Error: You haven't defined the language"))
+				    "Package babel Error: You haven't defined the language") ||
+				    contains(desc,
+				    "Package babel Error: You haven't loaded the option"))
 					retval |= ERROR_RERUN;
 				// get the line number:
 				int line = 0;