[CMake] CURVES_WITH_PINOCCHIO_SUPPORT automaticaly computed, fix #21

While here, add it to the .pc

CMakeLists.txt

@@ -19,12 +19,15 @@ CMAKE_POLICY(SET CMP0048 OLD)
 PROJECT(${PROJECT_NAME} CXX)
 
 ADD_REQUIRED_DEPENDENCY(eigen3)
-OPTION(CURVES_WITH_PINOCCHIO_SUPPORT "Build with pinocchio support" OFF)
+ADD_OPTIONAL_DEPENDENCY(pinocchio)
+OPTION(CURVES_WITH_PINOCCHIO_SUPPORT "Build with pinocchio support" ${PINOCCHIO_FOUND})
 IF(CURVES_WITH_PINOCCHIO_SUPPORT)
-  ADD_REQUIRED_DEPENDENCY(pinocchio)
+  IF(NOT PINOCCHIO_FOUND)
+    MESSAGE(FATAL_ERROR "CURVES_WITH_PINOCCHIO_SUPPORT selected, but pinocchio has not been found")
+  ENDIF(NOT PINOCCHIO_FOUND)
+  PKG_CONFIG_APPEND_CFLAGS("-DCURVES_WITH_PINOCCHIO_SUPPORT")
 ENDIF(CURVES_WITH_PINOCCHIO_SUPPORT)
 
-
 SET(BOOST_COMPONENTS unit_test_framework serialization)
 
 OPTION (BUILD_PYTHON_INTERFACE "Build the python binding" ON)