Fix generation of Doxygen documentation

doc/CMakeLists.txt

@@ -2,3 +2,5 @@ SET(DOXYGEN_XML_OUTPUT          "doxygen-xml"      PARENT_SCOPE)
 SET(DOXYGEN_FILE_PATTERNS       "*.h  *.hh  *.hxx" PARENT_SCOPE)
 SET(DOXYGEN_GENERATE_XML        "YES"              PARENT_SCOPE)
 SET(DOXYGEN_EXPAND_ONLY_PREDEF  "NO"               PARENT_SCOPE)
+
+SET(DOXYGEN_PREDEFINED          "IS_DOXYGEN"       PARENT_SCOPE)

python/collision-geometries.cc

@@ -45,6 +45,9 @@
 #include <hpp/fcl/BVH/BVH_model.h>
 
 #ifdef HPP_FCL_HAS_DOXYGEN_AUTODOC
+// FIXME for a reason I do not understand, doxygen fails to understand that
+// BV_splitter is not defined in hpp/fcl/BVH/BVH_model.h
+#include <hpp/fcl/internal/BV_splitter.h>
 #include "doxygen_autodoc/hpp/fcl/BVH/BVH_model.h"
 #include "doxygen_autodoc/hpp/fcl/shape/geometric_shapes.h"
 #endif