cmake: move Boost search to dedicated place

CMakeLists.txt

@@ -124,11 +124,9 @@ IF(BUILD_WITH_CASADI_SUPPORT)
 ENDIF(BUILD_WITH_CASADI_SUPPORT)
 
 SET(BOOST_REQUIRED_COMPONENTS filesystem serialization system)
-SET(BOOST_BUILD_COMPONENTS unit_test_framework)
 
 EXPORT_BOOST_DEFAULT_OPTIONS()
 ADD_PROJECT_DEPENDENCY(Boost REQUIRED COMPONENTS ${BOOST_REQUIRED_COMPONENTS})
-FIND_PACKAGE(Boost COMPONENTS ${BOOST_BUILD_COMPONENTS})
 
 IF(BUILD_PYTHON_INTERFACE)
   FINDPYTHON()

unittest/CMakeLists.txt

@@ -37,9 +37,8 @@ MACRO(ADD_OPTIONAL_COMPILE_DEPENDENCY PKG_CONFIG_STRING)
   ADD_DEPENDENCY(0 1 ${PKG_CONFIG_STRING} "${PKG_CONFIG_DEBUG_STRING}")
 ENDMACRO()
 
-# --- RULES -------------------------------------------------------------------
-# --- RULES -------------------------------------------------------------------
-# --- RULES -------------------------------------------------------------------
+# Find Boost.UnitTestFramework
+FIND_PACKAGE(Boost COMPONENTS unit_test_framework)
 
 # Math components
 ADD_PINOCCHIO_UNIT_TEST(eigen-basic-op)