cmake: remove REQUIRED

Author: jcarpent

CMakeLists.txt

@@ -121,7 +121,7 @@ endif()
 option(HPP_FCL_HAS_QHULL "use qhull library to compute convex hulls." FALSE)
 if(HPP_FCL_HAS_QHULL)
   CHECK_MINIMAL_CXX_STANDARD(11 ENFORCE)
-  ADD_PROJECT_DEPENDENCY(Qhull REQUIRED COMPONENTS qhull_r qhullcpp PKG_CONFIG_REQUIRES "qhull_r, qhuppcpp")
+  ADD_PROJECT_DEPENDENCY(Qhull COMPONENTS qhull_r qhullcpp PKG_CONFIG_REQUIRES "qhull_r, qhuppcpp")
   if(Qhull_FOUND)
     set(HPP_FCL_USE_SYSTEM_QHULL TRUE)
   else()