Let doxygen know how to handle 'requires' expressions.

diff --git a/doc/doxygen/options.dox.in b/doc/doxygen/options.dox.in
index b95298ffa2e09f8ef936ef16cbd2a3bafb8a61f2..045d5d88b73fe499d2fd5d3664550687cdccb2d4 100644 (file)
--- a/doc/doxygen/options.dox.in
+++ b/doc/doxygen/options.dox.in
@@ -184,6 +184,7 @@ PREDEFINED             = DOXYGEN=1 \
                          DEAL_II_HOST_DEVICE= \
                          DEAL_II_ALWAYS_INLINE= \
                          __device__= \
+                        DEAL_II_CXX20_REQUIRES=requires \
                          DEAL_II_WITH_ADOLC=1 \
                          DEAL_II_ADOLC_WITH_ADVANCED_BRANCHING=1 \
                          DEAL_II_ADOLC_WITH_ATRIG_ERF=1 \