Merge pull request #5468 from AVshokurov:master

cmake/OpenCVDetectCXXCompiler.cmake

@@ -76,17 +76,27 @@ elseif(CMAKE_COMPILER_IS_GNUCXX)
                 OUTPUT_STRIP_TRAILING_WHITESPACE)
 
   # Typical output in CMAKE_OPENCV_GCC_VERSION_FULL: "c+//0 (whatever) 4.2.3 (...)"
-  # Look for the version number
+  # Look for the version number, major.minor.build
   string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+" CMAKE_GCC_REGEX_VERSION "${CMAKE_OPENCV_GCC_VERSION_FULL}")
-  if(NOT CMAKE_GCC_REGEX_VERSION)
+  if(NOT CMAKE_GCC_REGEX_VERSION)#major.minor
     string(REGEX MATCH "[0-9]+\\.[0-9]+" CMAKE_GCC_REGEX_VERSION "${CMAKE_OPENCV_GCC_VERSION_FULL}")
   endif()
 
-  # Split the three parts:
+  if(CMAKE_GCC_REGEX_VERSION)
+    # Split the parts:
     string(REGEX MATCHALL "[0-9]+" CMAKE_OPENCV_GCC_VERSIONS "${CMAKE_GCC_REGEX_VERSION}")
 
     list(GET CMAKE_OPENCV_GCC_VERSIONS 0 CMAKE_OPENCV_GCC_VERSION_MAJOR)
     list(GET CMAKE_OPENCV_GCC_VERSIONS 1 CMAKE_OPENCV_GCC_VERSION_MINOR)
+  else()#compiler returned just the major version number
+    string(REGEX MATCH "[0-9]+" CMAKE_GCC_REGEX_VERSION "${CMAKE_OPENCV_GCC_VERSION_FULL}")
+    if(NOT CMAKE_GCC_REGEX_VERSION)#compiler did not return anything reasonable
+      set(CMAKE_GCC_REGEX_VERSION "0")
+      message(WARNING "GCC version not detected!")
+    endif()
+    set(CMAKE_OPENCV_GCC_VERSION_MAJOR ${CMAKE_GCC_REGEX_VERSION})
+    set(CMAKE_OPENCV_GCC_VERSION_MINOR 0)
+  endif()
 
   set(CMAKE_OPENCV_GCC_VERSION ${CMAKE_OPENCV_GCC_VERSION_MAJOR}${CMAKE_OPENCV_GCC_VERSION_MINOR})
   math(EXPR CMAKE_OPENCV_GCC_VERSION_NUM "${CMAKE_OPENCV_GCC_VERSION_MAJOR}*100 + ${CMAKE_OPENCV_GCC_VERSION_MINOR}")