add -ffriend_injection

Added CMake flag -ffriend_injection in order to prevent errors/warnings() with friend bool operators (29-31 lines in Variable.h). () Sometimes one has warnings only, sometimes - fatal errors (it seems to depend from compiler, root versions etc.)

CMakeLists.txt

@@ -23,6 +23,7 @@ if (CMAKE_BUILD_TYPE MATCHES DEBUG)
 endif ()
 
 set(CMAKE_CXX_FLAGS_DEBUG "-O0 -ggdb -g -DDEBUG -D__DEBUG -Wall -Wextra")
+set(CMAKE_CXX_FLAGS "-ffriend-injection")
 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELEASE} -ggdb")
 set(CMAKE_CXX_FLAGS_RELEASE "-O3 -march=native -ftree-vectorize -ffast-math -DNODEBUG")
 message(STATUS "Using CXX flags for ${CMAKE_BUILD_TYPE}: ${CMAKE_CXX_FLAGS_${CMAKE_BUILD_TYPE}}")