FindSuiteSparse.cmake: Correct `HAVE_SUITESPARSE_${_component}`

cmake/modules/FindSuiteSparse.cmake

@@ -164,8 +164,12 @@ endif()
 # check wether everything was found
 foreach(_component ${SUITESPARSE_COMPONENTS})
   # variable used for component handling
-  set(SuiteSparse_${_component}_FOUND (${_component}_LIBRARY AND ${_component}_INCLUDE_DIR))
-  set(HAVE_SUITESPARSE_${_component} SuiteSparse_${_component}_FOUND)
+  if(${_component}_LIBRARY AND ${_component}_INCLUDE_DIR)
+    set(SuiteSparse_${_component}_FOUND TRUE)
+  else()
+    set(SuiteSparse_${_component}_FOUND FALSE)
+  endif()
+  set(HAVE_SUITESPARSE_${_component} ${SuiteSparse_${_component}_FOUND})
   if(SuiteSparse_${_component}_FOUND)
     list(APPEND SUITESPARSE_INCLUDE_DIR "${${_component}_INCLUDE_DIR}")
     list(APPEND SUITESPARSE_LIBRARY "${${_component}_LIBRARY}")