Remove GCC 4.9 support. Minimum is now 5.0.

Author: TheMarex

.travis.yml

@@ -138,12 +138,12 @@ matrix:
       env: CCOMPILER='gcc-7' CXXCOMPILER='g++-7' BUILD_TYPE='Release' ENABLE_STXXL=On
 
     - os: linux
-      compiler: "gcc-4.9-release"
+      compiler: "gcc-5-release"
       addons: &gcc49
         apt:
           sources: ['ubuntu-toolchain-r-test']
-          packages: ['g++-4.9', 'libbz2-dev', 'libxml2-dev', 'libzip-dev', 'liblua5.2-dev', 'libtbb-dev', 'libboost-all-dev', 'ccache']
-      env: CCOMPILER='gcc-4.9' CXXCOMPILER='g++-4.9' BUILD_TYPE='Release'
+          packages: ['g++-5', 'libbz2-dev', 'libxml2-dev', 'libzip-dev', 'liblua5.2-dev', 'libtbb-dev', 'libboost-all-dev', 'ccache']
+      env: CCOMPILER='gcc-5' CXXCOMPILER='g++-5' BUILD_TYPE='Release'
 
     - os: linux
       compiler: "gcc-6-release"

CMakeLists.txt

@@ -101,10 +101,10 @@ if(WIN32 AND MSVC_VERSION LESS 1900)
   message(FATAL_ERROR "Building with Microsoft compiler needs Latest Visual Studio 2015 (Community or better)")
 endif()
 
-# Strictly require GCC>=4.9 and Clang>=3.4 - GCC 4.8 is already too old for C++14.
+# Strictly require GCC>=5.0 and Clang>=3.4 - GCC 4.8 is already too old for C++14.
 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
-  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9)
-    message(FATAL_ERROR "GCC>=4.9 required. In case you are on Ubuntu upgrade via ppa:ubuntu-toolchain-r/test")
+  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
+    message(FATAL_ERROR "GCC>=5.0 required. In case you are on Ubuntu upgrade via ppa:ubuntu-toolchain-r/test")
   endif()
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.4)
@@ -258,8 +258,7 @@ if(CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES MinRelSize OR CM
     endif()
 
     # Since gcc 4.9 the LTO format is non-standart ('slim'), so we need to use the build-in tools
-    if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND
-        NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9.0 AND NOT MINGW)
+    if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND NOT MINGW)
       find_program(GCC_AR gcc-ar)
       find_program(GCC_RANLIB gcc-ranlib)
       if ("${GCC_AR}" STREQUAL "GCC_AR-NOTFOUND" OR "${GCC_RANLIB}" STREQUAL "GCC_RANLIB-NOTFOUND")
@@ -287,12 +286,6 @@ if(CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES MinRelSize OR CM
         set(CMAKE_RANLIB ${LLVM_RANLIB})
       endif()
     endif()
-
-    if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9.0)
-      message(STATUS "Disabling LTO on GCC < 4.9.0 since it is broken, see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57038")
-      set(CMAKE_CXX_FLAGS "${OLD_CXX_FLAGS}")
-      set(ENABLE_LTO Off)
-    endif()
   endif()
 endif()
 
@@ -331,12 +324,6 @@ elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
   # using GCC
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OSRM_WARNING_FLAGS} -Werror=strict-overflow=1 -Wno-error=maybe-uninitialized -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 ${COLOR_FLAG} -fPIC -ftemplate-depth=1024")
 
-  # Disable missing field initializer since this has a lot of false positives with incomplete curly-braces
-  # initialization support on 4.9
-  if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.9)
-      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-error=missing-field-initializers")
-  endif()
-
   if(WIN32) # using mingw
     add_dependency_defines(-DWIN32)
     set(OPTIONAL_SOCKET_LIBS ws2_32 wsock32)