Set the iOS minimum version flag in the toolchain (#297)

* Set the iOS minimum deployment target

* Update unity_ios.cmake

* Update readme.md

Author: a-maurice

cmake/unity_ios.cmake

@@ -16,7 +16,13 @@ message(STATUS "gcc found at: ${CMAKE_C_COMPILER}")
 message(STATUS "g++ found at: ${CMAKE_CXX_COMPILER}")
 message(STATUS "Using iOS SDK: ${CMAKE_OSX_SYSROOT}")
 
-set(CMAKE_OSX_SYSROOT "iphoneos;iphonesimulator")
+set(CMAKE_SYSTEM_NAME "iOS")
+# In order to build for both device and simulator, this needs to be empty,
+# or the CMAKE_OSX_DEPLOYMENT_TARGET setting below is not handled correctly.
+# Note, this seems to cause an issue with repeating builds on some cmake versions,
+# the long term fix will likely be to not handle both device and simulator with
+# the same toolchain, and instead merge the libraries after the fact.
+set(CMAKE_OSX_SYSROOT "")
 set(CMAKE_OSX_ARCHITECTURES "arm64;armv7;x86_64;i386" CACHE STRING "")
 set(CMAKE_XCODE_EFFECTIVE_PLATFORMS "-iphoneos;-iphonesimulator")
 set(IOS_PLATFORM_LOCATION "iPhoneOS.platform;iPhoneSimulator.platform")
@@ -25,6 +31,7 @@ set(CMAKE_IOS_INSTALL_UNIVERSAL_LIBS "YES")
 set(CMAKE_XCODE_ATTRIBUTE_ONLY_ACTIVE_ARCH "NO")
 set(CMAKE_XCODE_ATTRIBUTE_CODE_SIGNING_REQUIRED "NO")
 set(CMAKE_XCODE_ATTRIBUTE_ENABLE_BITCODE "YES")
+set(CMAKE_OSX_DEPLOYMENT_TARGET "8.0" CACHE STRING "")
 
 # skip TRY_COMPILE checks
 set(CMAKE_CXX_COMPILER_WORKS TRUE)

docs/readme.md

@@ -160,6 +160,7 @@ Release Notes
     - General: Minimum supported editor version is now Unity 2018.
     - General (Editor, macOS): Add support for Apple Silicon chips.
     - General (iOS): Firebase Unity on iOS is now built using Xcode 13.3.1.
+    - General (iOS): Fixed crash when running on iPhoneOS 12 and older.
     - Analytics: Removed deprecated event names and parameters.
     - Crashlytics (Android): Fixed a bug with missing symbols when enabling
       minification via proguard.