diff --git a/doc/doxy/Doxyfile b/doc/doxy/Doxyfile
index 904da9377..ed8705596 100644
--- a/doc/doxy/Doxyfile
+++ b/doc/doxy/Doxyfile
@@ -314,9 +314,9 @@ EXPAND_ONLY_PREDEF     = YES
 SEARCH_INCLUDES        = YES
 INCLUDE_PATH           = 
 INCLUDE_FILE_PATTERNS  = 
-PREDEFINED             = BOOST_CONCEPT_REQUIRES(x)= \
-                         BOOST_CONCEPT_ASSERT(x) = \
-                         BOOST_STATIC_ASSERT(x) = \
+PREDEFINED             = BOOST_CONCEPT_REQUIRES(x) \
+                         BOOST_CONCEPT_ASSERT(x) \
+                         BOOST_STATIC_ASSERT(x) \
                          DOXYGEN_SHOULD_SKIP_THIS \
                          DOXYGEN_NO_DISPATCH \
                          DOXYGEN_NO_IMPL \