Update README.md

[skip ci]
Merge branch 'master' into update
Set XCODE_ATTRIBUTE_ONLY_ACTIVE_ARCH to "NO" to build all listed architectures
Update README.md

[skip ci]
Update README.md

[skip ci]
Set sugar_set_xcode_ios_sdkroot in sugar_add_ios_library function
Merge branch 'master' into update [skip ci]