tree 8fb8decc09361dfeb93045fab1ee6e5575742a5b
parent 799fd5019269b8d08c2002ae08b17fd01046a9aa
author Alex Stewart <alexs.mac@gmail.com> 1529256654 +0100
committer Alex Stewart <alexs.mac@gmail.com> 1529520192 +0100

Replace (MSVC/GCC/CLANG)_VERSION with CMAKE_CXX_COMPILER_VERSION.

- As raised in issue #377, GCC_VERSION is not always defined, in which
  case we were not enabling compiler optimisations.
- CMAKE_CXX_COMPILER_VERSION is the more modern, uniform method to
  verify the compiler version.
- Also removes legacy Apple-GCC (i.e. Apple's fork of GCC prior to their
  switch to Clang) logic, and Xcode 4.x logic (in June 2018, Xcode 9.x
  is the current version).
- Also removes addition of -march=native on Linux (was not added for
  OS X).  If users wish to append -march=native (which will affect the
  portability of the resulting output) they can do so manually as now
  explained in the docs.
- Fixes check for Clang on OS X.  As per CMP0025 (CMake 3.0+)
  CMAKE_CXX_COMPILER_ID reports AppleClang on OS X, not Clang. Thus
  using: if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang") would fail for
  AppleClang.  Instead, MATCHES should be used instead of STREQUAL to
  support both Clang & AppleClang.

Change-Id: I9647030b76f4b85a9ef2deea82d80ed79812ae33