Can't find qwt when use cmake of Elmer

Question

I'm trying to install Elmer with GUI, the qt5 and Qwt are required in CMakeLists.txt. I installed Qt5 and Qwt via Homebrew, but seems they can not find them.

The CMakeLists.txt looks like:

IF(WITH_QWT)
  ADD_DEFINITIONS(-DEG_QWT)
  FIND_PACKAGE(Qwt REQUIRED
              )
  FIND_PATH(QWT_INCLUDE_DIR qwt.h)
#  SET(QWT_INCLUDE_DIR "c:/b/qwt-6.1.0/include")
#  SET(QWT_LIBRARY "c:/b/qwt-6.1.0/lib/qwt.dll")
  MESSAGE(STATUS "  [ElmerGUI] Qwt:             " ${Qwt_FOUND})
  MESSAGE(STATUS "  [ElmerGUI] QWT_LIBRARY:     " ${QWT_LIBRARY})
  MESSAGE(STATUS "  [ElmerGUI] QWT_INCLUDE_DIR: " ${QWT_INCLUDE_DIR})
  MESSAGE(STATUS "------------------------------------------------")
ENDIf()

And the error message I got is:

CMake Error at ElmerGUI/CMakeLists.txt:64 (FIND_PACKAGE):
  Could not find a package configuration file provided by "Qwt" with any of
  the following names:

    QwtConfig.cmake
    qwt-config.cmake

  Add the installation prefix of "Qwt" to CMAKE_PREFIX_PATH or set "Qwt_DIR"
  to a directory containing one of the above files.  If "Qwt" provides a
  separate development package or SDK, be sure it has been installed.

I tried to add PATHS to CMakeLists.txt and it won't works. Could someone tell me where I did wrong? Thanks in advance.