added arm layer compilation for arm-linux system (#316)

src/CMakeLists.txt

@@ -39,6 +39,8 @@ macro(ncnn_add_layer class)
         # optimized implementation for armv7 aarch64
         if((ANDROID AND ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv7-a"))
             OR (ANDROID AND ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "aarch64"))
+            OR (UNIX AND ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv7l"))
+            OR (UNIX AND ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "aarch64"))
             OR (IOS AND ("${CMAKE_OSX_ARCHITECTURES}" STREQUAL "armv7"))
             OR (IOS AND ("${CMAKE_OSX_ARCHITECTURES}" STREQUAL "arm64"))
             OR (IOS AND ("${CMAKE_OSX_ARCHITECTURES}" STREQUAL "armv7;arm64")))