disabling LTO for gcc >= 7

CMakeLists.txt

@@ -181,9 +181,15 @@ elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
 	set(STORM_COMPILER_ID "AppleClang")
 	set(CMAKE_MACOSX_RPATH ON)	
 elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+	set(GCC ON)
 	# using GCC
 	if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
 		message(FATAL_ERROR "gcc version must be at least 5.0.")
+	elseif (CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL 7.0 OR CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 7.0)
+		if (STORM_USE_LTO)
+			set(STORM_USE_LTO OFF)
+			message(WARNING "Disabling link-time optimization, because of known incompatibility of LTO with gcc >= 7.")
+		endif()
 	endif()
 
 	set(STORM_COMPILER_GCC ON)