diff --git a/.gitignore b/.gitignore
index d704d1e758cd..8ab2dcda3246 100644
--- a/.gitignore
+++ b/.gitignore
@@ -179,3 +179,6 @@ tests/*/project/proj.android/.settings/org.eclipse.buildship.core.prefs
 # tmp folder for temp usage
 tmp/
 temp/
+
+# external libs zip
+*.zip
diff --git a/cmake/ios.toolchain.cmake b/cmake/ios.toolchain.cmake
index 5b2b1de6685b..3d9bd3050c47 100644
--- a/cmake/ios.toolchain.cmake
+++ b/cmake/ios.toolchain.cmake
@@ -35,8 +35,9 @@ set(UNIX True)
 set(APPLE True)
 set(IOS True)
 
-# Required as of cmake 2.8.10
-set(CMAKE_OSX_DEPLOYMENT_TARGET "" CACHE STRING "Force unset of the deployment target for iOS" FORCE)
+# support iOS on cmake 3.11+
+# cmake 3.11 milestone feature, https://gitlab.kitware.com/cmake/cmake/issues/17431 
+set(CMAKE_OSX_DEPLOYMENT_TARGET "8.0" CACHE STRING "set of the deployment target for iOS" FORCE)
 
 # Determine the cmake host system version so we know where to find the iOS SDKs
 find_program(CMAKE_UNAME uname /bin /usr/bin /usr/local/bin)