[Rework] Require CMake 3.9 to work, remove manual lto crap

CMakeLists.txt

@@ -5,7 +5,7 @@
 #
 
 ############################# INITIAL SECTION #############################################
-CMAKE_MINIMUM_REQUIRED(VERSION 3.1 FATAL_ERROR)
+CMAKE_MINIMUM_REQUIRED(VERSION 3.9 FATAL_ERROR)
 
 SET(RSPAMD_VERSION_MAJOR 2)
 SET(RSPAMD_VERSION_MINOR 1)
@@ -769,30 +769,21 @@ ENDIF(SUPPORT_FPIC)
  # Optimization flags
 IF(NOT CMAKE_C_OPT_FLAGS)
 	IF(ENABLE_OPTIMIZATION MATCHES "ON")
-	CHECK_C_COMPILER_FLAG(-flto SUPPORT_FLTO)
-	IF(SUPPORT_FLTO)
-		IF(NOT CMAKE_GCC_AR OR NOT CMAKE_GCC_RANLIB)
-			FIND_PROGRAM(CMAKE_GCC_AR NAMES "gcc-ar")
-			FIND_PROGRAM(CMAKE_GCC_RANLIB NAMES "gcc-ranlib")
-			MARK_AS_ADVANCED(CMAKE_GCC_AR CMAKE_GCC_RANLIB)
+		SET(CMAKE_C_OPT_FLAGS "-g -O2")
+		IF(${CMAKE_VERSION} VERSION_GREATER "3.9.0")
+			CMAKE_POLICY(SET CMP0069 NEW)
+			INCLUDE(CheckIPOSupported)
+			check_ipo_supported(RESULT SUPPORT_LTO OUTPUT LTO_DIAG )
+			if(SUPPORT_LTO)
+				SET(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
+			else()
+				message(WARNING "IPO is not supported: ${LTO_DIAG}")
+			endif()
 		ENDIF()
-		IF(CMAKE_GCC_AR AND CMAKE_GCC_RANLIB)
-			SET(CMAKE_C_OPT_FLAGS "-g -O3 -flto")
-			SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -flto")
-			SET(CMAKE_C_ARCHIVE_CREATE "${CMAKE_GCC_AR} cr <TARGET> <LINK_FLAGS> <OBJECTS>")
-			SET(CMAKE_C_ARCHIVE_APPEND "${CMAKE_GCC_AR} r <TARGET> <LINK_FLAGS> <OBJECTS>")
-			SET(CMAKE_C_ARCHIVE_FINISH "${CMAKE_GCC_RANLIB} <TARGET>")
-			SET(CMAKE_CXX_ARCHIVE_CREATE "${CMAKE_GCC_AR} cr <TARGET> <LINK_FLAGS> <OBJECTS>")
-			SET(CMAKE_CXX_ARCHIVE_APPEND "${CMAKE_GCC_AR} r <TARGET> <LINK_FLAGS> <OBJECTS>")
-			SET(CMAKE_CXX_ARCHIVE_FINISH "${CMAKE_GCC_RANLIB} <TARGET>")
-		ENDIF()
-	ELSE()
-		SET(CMAKE_C_OPT_FLAGS "-g -O3")
-	ENDIF()
 	ELSE(ENABLE_OPTIMIZATION MATCHES "ON")
 		IF(ENABLE_FULL_DEBUG MATCHES "ON")
 			ADD_DEFINITIONS(-DFULL_DEBUG)
-			SET(CMAKE_C_OPT_FLAGS "-g -O0")
+			SET(CMAKE_C_OPT_FLAGS "-g -Og")
 		ELSE(ENABLE_FULL_DEBUG MATCHES "ON")
 			SET(CMAKE_C_OPT_FLAGS "-g -O2")
 		ENDIF(ENABLE_FULL_DEBUG MATCHES "ON")
@@ -800,7 +791,7 @@ IF(NOT CMAKE_C_OPT_FLAGS)
 ENDIF(NOT CMAKE_C_OPT_FLAGS)
 
 IF(ENABLE_COVERAGE)
-	SET(CMAKE_C_OPT_FLAGS "-g -O0")
+	SET(CMAKE_C_OPT_FLAGS "-g -Og")
 	SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} --coverage")
 	SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --coverage")
 	SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --coverage")

contrib/replxx/CMakeLists.txt

@@ -1,7 +1,4 @@
 # -*- mode: CMAKE; -*-
-
-cmake_minimum_required(VERSION 3.0)
-
 project( replxx VERSION 0.0.2 LANGUAGES CXX C )
 message(STATUS "Build mode: ${CMAKE_BUILD_TYPE}")