This is a paid asset, but now you can download IOS Deploy Free.
Detail this asset from Unity Store: Original Link
IOS Deploy v2.1
“If possible, please buy the package to support the developer”
This plugin allows you add additional params to the Xcode project on unity building phase.
Online Documentation | Forum Thread
* Compiler Flags
* Linker Flags
* Plist Values
For example if you have IOS plugin with requires some flags or frameworks to be added in compiled IOS project, or you did your own plugin for your game, no need to add it manually every time. IOS Deploy plugin will do this for you on Unity building phase.