Fix check of targets in package config when GFLAGS_USE_TARGET_NAMESPACE

cmake/config.cmake.in

@@ -36,8 +36,8 @@ set (@PACKAGE_PREFIX@_INCLUDE_DIR "${_INSTALL_PREFIX}/@INCLUDE_INSTALL_DIR@")
 
 if (@PACKAGE_NAME@_FIND_COMPONENTS)
   foreach (@PACKAGE_NAME@_FIND_COMPONENT IN LISTS @PACKAGE_NAME@_FIND_COMPONENTS)
-    if (@PACKAGE_NAME@_FIND_REQUIRED_${@PACKAGE_NAME@_FIND_COMPONENT} AND NOT TARGET @PACKAGE_NAME@_${@PACKAGE_NAME@_FIND_COMPONENT})
-      message (FATAL_ERROR "Package @PACKAGE_NAME@ was installed without required component ${@PACKAGE_NAME@_FIND_COMPONENT}!")
+    if (@PACKAGE_NAME@_FIND_REQUIRED_${@PACKAGE_NAME@_FIND_COMPONENT} AND NOT TARGET ${@PACKAGE_PREFIX@_TARGET_PREFIX}@PACKAGE_NAME@_${@PACKAGE_NAME@_FIND_COMPONENT})
+      message (FATAL_ERROR "Package @PACKAGE_NAME@ was installed without required component ${@PACKAGE_PREFIX@_TARGET_PREFIX}${@PACKAGE_NAME@_FIND_COMPONENT}!")
     endif ()
   endforeach ()
   list (GET @PACKAGE_NAME@_FIND_COMPONENTS 0 @PACKAGE_NAME@_FIND_COMPONENT)