change MathJax CDN

https://cdn.mathjax.org is shutting down, so switch to the recommended alternative CDN.

Fixes #4169

diff --git a/doc/doxygen/CMakeLists.txt b/doc/doxygen/CMakeLists.txt
index e800200dad3685883d81b68d12d2040bf5579fb4..4eafc72bfb39041bc95e93ad335070f2cce9f7ea 100644 (file)
--- a/doc/doxygen/CMakeLists.txt
+++ b/doc/doxygen/CMakeLists.txt
@@ -72,12 +72,9 @@ IF(DEAL_II_DOXYGEN_USE_MATHJAX)
   IF(MATHJAX_PATH AND NOT DEAL_II_DOXYGEN_USE_ONLINE_MATHJAX)
     SET(_mathjax_relpath ${MATHJAX_PATH})
     MESSAGE(STATUS "Using local MathJax: " ${MATHJAX_PATH})
-    SET(MATHJAX_RELPATH_CONFIG "MATHJAX_RELPATH = ${MATHJAX_PATH}")
   ELSE()
-    SET(_mathjax_relpath "https://cdn.mathjax.org/mathjax/latest")
+    SET(_mathjax_relpath "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/")
     MESSAGE(STATUS "Using web-based MathJax: " ${_mathjax_relpath})
-    SET(MATHJAX_RELPATH_CONFIG "")
-    MESSAGE(STATUS "Using default web-based MathJax")
   ENDIF()
 ELSE()
   SET(_use_mathjax NO)