GMP & MPFR not found by cmake, but are installed - macos

Question

I'm trying to compile the plll library which require boost, GMP and MPFR on mac os X 10.11.
I've installed boost, GMP and MPFR by homebrew, then i've launched cmake in a dir build in plll, but I get that error :
By not providing "FindMPFR.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "MPFR", but
CMake did not find one.
Could not find a package configuration file provided by "MPFR" with any of
the following names:
MPFRConfig.cmake
mpfr-config.cmake
Add the installation prefix of "MPFR" to CMAKE_PREFIX_PATH or set
"MPFR_DIR" to a directory containing one of the above files. If "MPFR"
provides a separate development package or SDK, be sure it has been
installed.
And the same for GMP if I change the order of GMP and MPFR in the Librairies.txt used by cmake.
After that i've install the librairies by hand and they are in/usr/local/include. The make check of GMP is perfect so I guess that the installation is ok.
But still the same error message. I've also tried to add a FindMPFR.cmake file but no change at all.
Here is the part of the Libraries.txt which is concerned:
find_package(MPFR REQUIRED)
include_directories(${MPFR_INCLUDES})
if(NOT MPFR_FOUND)
message(FATAL_ERROR "Could not find MPFR!")
endif(NOT MPFR_FOUND)
set(libraries ${libraries} ${MPFR_LIBRARIES})
set(libraries_shared ${libraries_shared} ${MPFR_LIBRARIES})
find_package(GMP REQUIRED)
include_directories(${GMP_INCLUDE_DIR})
if(NOT (GMP_INCLUDE_DIR AND GMP_LIBRARIES))
message(FATAL_ERROR "Could not find GMP!")
endif(NOT (GMP_INCLUDE_DIR AND GMP_LIBRARIES))
set(libraries ${libraries} ${GMP_LIBRARIES})
set(libraries_shared ${libraries_shared} ${GMP_LIBRARIES})
The strange part of that is that I've no problem with Boost...