OpenCV SuperBuild fails with gcc 7+

Description

At some point gcc changed the output of its -dumpversion argument. This breaks OpenCV's cmake/OpenCVDetectCXXCompiler.cmake which parses this output.

When building OTB SuperBuild the error in OPENCV/src/OPENCV-stamp/OPENCV-configure-err.log is:

CMake Error at cmake/OpenCVDetectCXXCompiler.cmake:82 (list):
  list GET given empty list
Call Stack (most recent call first):
  CMakeLists.txt:91 (include)


CMake Error at cmake/OpenCVDetectCXXCompiler.cmake:83 (list):
  list GET given empty list
Call Stack (most recent call first):
  CMakeLists.txt:91 (include)


CMake Error at cmake/OpenCVDetectCXXCompiler.cmake:86 (math):
  math cannot parse the expression: "*100 + ": syntax error, unexpected
  exp_TIMES, expecting exp_PLUS or exp_MINUS or exp_OPENPARENT or exp_NUMBER
  (1)
Call Stack (most recent call first):
  CMakeLists.txt:91 (include)


CMake Error at cmake/OpenCVCompilerOptions.cmake:21 (else):
  A duplicate ELSE command was found inside an IF block.
Call Stack (most recent call first):
  CMakeLists.txt:432 (include)

This is fixed in more recent version of OpenCV. See this commit from 2015 for example: https://github.com/opencv/opencv/commit/bbe007159ad6b99e15f47171b7b6be7c892ca9fa#diff-b119273dbadd24865d7eb8b2c2aa1f47

The latest version of that file in OpenCV does not even rely on -dumpversion anymore.

What is the proper OTB fix? A superbuild patch or maybe upgrade opencv?

Steps to reproduce

SuperBuild with gcc 7.

Configuration information

Ubuntu 17.10, gcc 7.