Add compile option for enabling NEON

CMakeLists.txt

@@ -196,6 +196,7 @@ OCV_OPTION(ENABLE_SSSE3               "Enable SSSE3 instructions"
 OCV_OPTION(ENABLE_SSE41               "Enable SSE4.1 instructions"                               OFF  IF ((CV_ICC OR CMAKE_COMPILER_IS_GNUCXX) AND (X86 OR X86_64)) )
 OCV_OPTION(ENABLE_SSE42               "Enable SSE4.2 instructions"                               OFF  IF (CMAKE_COMPILER_IS_GNUCXX AND (X86 OR X86_64)) )
 OCV_OPTION(ENABLE_AVX                 "Enable AVX instructions"                                  OFF  IF ((MSVC OR CMAKE_COMPILER_IS_GNUCXX) AND (X86 OR X86_64)) )
+OCV_OPTION(ENABLE_NEON                "Enable NEON instructions"                                 OFF  IF (CMAKE_COMPILER_IS_GNUCXX AND ARM) )
 OCV_OPTION(ENABLE_NOISY_WARNINGS      "Show all warnings even if they are too noisy"             OFF )
 OCV_OPTION(OPENCV_WARNINGS_ARE_ERRORS "Treat warnings as errors"                                 OFF )
 OCV_OPTION(ENABLE_WINRT_MODE          "Build with Windows Runtime support"                       OFF  IF WIN32 )

cmake/OpenCVCompilerOptions.cmake

@@ -161,6 +161,10 @@ if(CMAKE_COMPILER_IS_GNUCXX)
     endif()
   endif()
 
+  if(ENABLE_NEON)
+    add_extra_compiler_option(-mfpu=neon)
+  endif()
+
   # Profiling?
   if(ENABLE_PROFILING)
     add_extra_compiler_option("-pg -g")