1. Use `xcrun` to run `ibtool` (and `actool`) and avoid toolchain mismatches
2. Set `DEVELOPER_DIR` so everyone (well `xcrun`) use the same toolchain
3. Workaround for `macos-arm64` issue (FB8827920)
* Start `ibtool` as an `Apple` [Silicon] process
* This will ensure the `ibtoold` daemon is also running as `Apple`
* If `ibtoold` is run as `Intel` then `ibtool` asserts and build fail
```
LaunchScreen.storyboard : error : 2020-10-26 14:24:52.757 ibtoold[37142:6681382] [MT] DVTAssertions: Warning in /Library/Caches/com.apple.xbs/Sources/IDEInterfaceBuilder/IDEInterfaceBuilder-17506/InterfaceBuilderKit/Utilities/IBAbstractInterfaceBuilderPlatformToolManager.m:481
LaunchScreen.storyboard : error : Details: Failed to attach to IBAgent-iOS with error: Error Domain=com.apple.InterfaceBuilder Code=-1 "Encountered an error communicating with IBAgent-iOS." UserInfo={NSLocalizedFailureReason=IBAgent-iOS (37146) failed to launch and exited with status 10, NSUnderlyingError=0x7fa4e58fc760 {Error Domain=com.apple.InterfaceBuilder Code=-1 "Failed to launch IBAgent-iOS via CoreSimulator spawn" UserInfo={NSLocalizedDescription=Failed to launch IBAgent-iOS via CoreSimulator spawn, NSUnderlyingError=0x7fa4e5e8a900 {Error Domain=com.apple.InterfaceBuilder Code=-1 "Failed to handshake with platform tool" UserInfo={NSLocalizedFailureReason=Failed to open connection over FIFOs with platform tool, NSLocalizedDescription=Failed to handshake with platform tool, NSUnderlyingError=0x7fa4e5e237c0 {Error Domain=com.apple.InterfaceBuilder Code=-1 "" UserInfo=0x7fa4e5e8bba0 (not displayed)}}}}}, NSLocalizedRecoverySuggestion=Please check Console.app for crash reports for "IBAgent-iOS" for further information., NSLocalizedDescription=Encountered an error communicating with IBAgent-iOS.}
LaunchScreen.storyboard : error : Object: <IBCocoaTouchToolManager>
LaunchScreen.storyboard : error : Method: +_THREADSAFE_launchNewToolWithLaunchContext:executionContext:toolProxyClass:proxyDelegate:failureContext:requestingMethod:error:forReason:
LaunchScreen.storyboard : error : Thread: <NSThread: 0x7fa4e341af70>{number = 1, name = main}
LaunchScreen.storyboard : error : Please file a bug at https://feedbackassistant.apple.com with this warning message and any useful information you can provide.
LaunchScreen.storyboard : error : 2020-10-26 14:24:52.766 ibtoold[37142:6681382] [MT] IBPlatformTool: *** Failed to launch tool with description <IBCocoaTouchPlatformToolDescription: 0x7fa4e5f34160> System content for IBCocoaTouchFramework-fourteenAndLater <IBScaleFactorDeviceTypeDescription: 0x7fa4e5f2fb50> scaleFactor=2x, renderMode.identifier=(null): Encountered an error communicating with IBAgent-iOS. (Failure reason: IBAgent-iOS (37146) failed to launch and exited with status 10): Failed to launch IBAgent-iOS via CoreSimulator spawn: Failed to handshake with platform tool (Failure reason: Failed to open connection over FIFOs with platform tool): : Failed to open FIFOs for handshaking with platform tool (Failure reason: IBAgent-iOS exited before we could handshake)
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1425,3): error : ibtool exited with code 1
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1425,3): error :
LaunchScreen.storyboard : ibtool error : Encountered an error communicating with IBAgent-iOS.
```
Note: `main` has diverged quite a bit (net6 support) so this pull request
will need to be re-worked (it won't apply)
Fixes https://github.com/xamarin/xamarin-macios/issues/4634
* [xcode12] Initial bump for Xcode 12 GM
* [tests][intro] We cannot load CoreNFC framework on iOS simulator anymore
* [tests][xtro] New Metal API are not abstract (before XAMCORE_4_0)
* [tests][intro] Fix crash when CSLocalizedString 'description' selector is called
* [tests][xtro] Add support for excluding platforms
Based on `Make.config` variables `INCLUDE_[IOS|TVOS|WATCH|MAC]`
This required moving some entries (common -> macOS) to keep the
sanitizer happy.
* [xtro] Ignore Intents watchOS differences since they will likely match iOS in the future
* Update to use Xcode 12 GMb instead of the old GM
* [tests][xtro] Remove OSLog for iOS and tvOS (changed in GM)
* [tests][msbuild] Disable FrameworkListTest based on the active/disabled platforms
* [tests][msbuild] Track new directory/file inside CoreML projects
* [mlaunch] Bump maccore and disable mlaunch if mac build is disabled
New commits in xamarin/maccore:
* xamarin/maccore@ba332d4d07 Disable mlaunch if Mac is not built (#2314)
Diff: 87a96d21c9..ba332d4d07
Co-authored-by: Sebastien Pouliot <sebastien.pouliot@microsoft.com>
- Fixes https://github.com/xamarin/xamarin-macios/issues/9458
- Defining the variable over multiple lines changes output to include incorrect newline
- Auto tests did not catch, as they don't sign on bots due to infrastructure issues.
- Was refactored _after_ manual tests and not retested
If the path to the project or compiled app has spaces, then the URI
that is generated for the on-demand resources in the
AssetPackManifestTemplate.plist file is invalid
Fixes https://github.com/xamarin/xamarin-macios/issues/8452
Co-authored-by: Matthew Leibowitz <mattleibow@live.com>
If the path to the project or compiled app has spaces, then the URI
that is generated for the on-demand resources in the
AssetPackManifestTemplate.plist file is invalid
Fixes https://github.com/xamarin/xamarin-macios/issues/8452
Co-authored-by: Matthew Leibowitz <mattleibow@live.com>
- This commit adds a hook, "AdditionalAppExtensions", to the msbuild to allow
extensions written in other languages, such as Swift, to be embedded and signed in an
Xamarin App bundle easily.
- Example:
<AdditionalAppExtensions Include="$(MSBuildProjectDirectory)/../../native">
<Name>NativeTodayExtension</Name>
<BuildOutput Condition="'$(Platform)' == 'iPhone'">build/Debug-iphoneos</BuildOutput>
<BuildOutput Condition="'$(Platform)' == 'iPhoneSimulator'">build/Debug-iphonesimulator</BuildOutput>
</AdditionalAppExtensions>
`GetMinimumOSVersion` should not be run if there's no Mac available because it depends on `_DetectSdkLocations` to calculate the value of `_SdkVersion`, and this will only happen if there's a Mac connected. This change fixes offline builds (plain IL builds) and Hot Restart builds on Windows.
* [msbuild] Changes GetMinimumOSVersionTaskBase to use ITaskItem for inputs
From Visual Studio we need the input files to be instead of plain strings to identify the files that need to be copied to the Mac
* Adds null check for AppManifest in GetMinimumOSVersionTaskBase
This will ensure the file isn't kept open until the GC runs, and then
sometimes it can prevent other tasks or targets from opening it if the GC
hasn't run.
Fixes this problem:
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 1 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 2 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 3 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 4 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 5 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 6 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 7 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 8 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 9 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 10 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): error MSB3027: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Exceeded retry count of 10. Failed.
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): error MSB3021: Unable to copy file "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
Fixes https://github.com/xamarin/maccore/issues/2137.
Fixes https://github.com/xamarin/xamarin-macios/issues/8940.
Co-authored-by: Rolf Bjarne Kvinge <rolf@xamarin.com>
This will ensure the file isn't kept open until the GC runs, and then
sometimes it can prevent other tasks or targets from opening it if the GC
hasn't run.
Fixes this problem:
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 1 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 2 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 3 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 4 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 5 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 6 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 7 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 8 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 9 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): warning MSB3026: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Beginning retry 10 in 1000ms. Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): error MSB3027: Could not copy "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Exceeded retry count of 10. Failed.
/Library/Frameworks/Mono.framework/Versions/6.10.0/lib/mono/msbuild/Current/bin/Microsoft.Common.CurrentVersion.targets(4203,5): error MSB3021: Unable to copy file "obj/Debug/Fantas.dll" to "../../../lib/Debug/MonoGame/xamarinios/Fantas.dll". Sharing violation on path [...]/lib/Debug/MonoGame/xamarinios/Fantas.dll
Fixes https://github.com/xamarin/maccore/issues/2137.
Fixes https://github.com/xamarin/xamarin-macios/issues/8940.
Also rework the class hierarchy a little bit, so that Xamarin.iOS and
Xamarin.Mac are identical:
CompileAppManifestTaskBase
└─── iOS/CompileAppManifestTaskCore
│ └─── iOS/CompileAppManifest
└─── Mac/CompileAppManifestTaskCore
│ └─── Mac/CompileAppManifest
* Create a simple Xamarin.Utils.Execution class that can handle all our
process execution needs:
* Captures or streams stdout/stderr (in UTF8).
* Supports async
* Supports a timeout
* Does not depend on any other source file we have, only uses BCL API.
* Have the execution helper classes from mtouch/mmp
(Xamarin.BundlerDriver.RunCommand) and the tests
(Xamarin.Tests.ExecutionHelper) use this new class.
* Some simplifications were made:
* All API that took a string array for the environment now takes a
Dictionary<string, string>.
* The Driver.RunCommand methods were split out to a separate file. This
file also contains a Verbosity field, which is conditioned on not being
in mtouch nor mmp, which makes including this file from other projects
simpler (such as bgen - in particular bgen was modified to use this
Verbosity field instead of its own).
This makes it possible for several other tasks to take the MinimumOSVersion as
direct input, instead of the app manifest's path. Previously the app manifest
(Info.plist) was loaded and parsed in each task, slightly differently in each
place, and in addition there are differences between macOS and other
platforms, which made it even worse. This code refactoring also made it
possible to remove an error code which wasn't necessary anymore.
This task also computes the default MinimumOSVersion if none is specified in
the app manifest.
There is one breaking change: a library project could previously specify an
inexistent Info.plist, and it would build fine. This will now result in a
"Error loading 'Info.plist': File not found" error. This is trivial to fix:
just remove the Info.plist from the project file (or an alternative solution
could be to condition the inclusion of the Info.plist in the project file on
the existence of the Info.plist).
New commits in xamarin/Xamarin.MacDev:
* xamarin/Xamarin.MacDev@a1bc6f3 [Xamarin.MacDev] Split IAppleSdkVersion.TryParse in two methods. (#73)
Diff: 45c5a680e2..a1bc6f39b3
* [msbuild] Share the DeviceSpecificIntermediateOutputPath property.
We don't technically need this value for Xamarin.Mac, but many of the targets
that can be shared need to use this for Xamarin.iOS, so set this value for
Xamarin.Mac as well. It will always be the default IntermediateOutputPath for
Xamarin.Mac, while for Xamarin.iOS it might be changed in
_ComputeTargetArchitectures.
* [msbuild] Remove usage in Xamarin.Mac of a variable that was always empty in the past.
* [msbuild] Unify MtouchDebug and MmpDebug into _Debug.
* [msbuild] Use _BundlerDebug instead of _Debug.
_Debug is too generic, and more likely to clash with someone else.
Also fix several tests to work when executed from within VS due to some difference
There's also a change to the MtouchTask: lookup of framework assemblies won't
succeed anymore if the path to the assembly is just an unrooted filename
(which may happen to be a file in the current directory (as a test proved
accidentally) - in which case it will never be a framework assembly).
Unfortunately this won't make all tests pass, around 20 tests will still fail with:
#RunTarget-ErrorCount
The "GetReferenceNearestTargetFrameworkTask" task could not be instantiated from the assembly "/Library/Frameworks/Mono.framework/Versions/Current/lib/mono/msbuild/15.0/bin/NuGet.Build.Tasks.dll". Please verify the task assembly has been built using the same version of the Microsoft.Build.Framework assembly as the one installed on your computer and that your host application is not missing a binding redirect for Microsoft.Build.Framework. Specified cast is not valid.
The "GetReferenceNearestTargetFrameworkTask" task has been declared or used incorrectly, or failed during construction. Check the spelling of the task name and the assembly name.
Expected: 0
But was: 2
but I couldn't figure out how to fix these errors.
Fixes https://github.com/xamarin/xamarin-macios/issues/5042.
* [src] Remove Classic code from System.Net.Http.
* [src] Remove Classic code from the ObjCRuntime namespace.
* [src] Remove Classic code from the native types.
* [src] Remove the Classic defines from the makefiles.
* [src] Remove Classic code from the Constants class.
* [src] Update project files to remove XAMCORE_2_0 and __UNIFIED__.
* [src] Remove Classic code from the MonoNativeFunctionWrapper and MonoPInvokeCallback attributes.
* [src] Update README to remove outdated docs about XAMCORE_2_0.
* [d16-7] [registrar] Remove Classic Code.
* Bump Touch.Unit.
New commits in spouliot/Touch.Unit:
* spouliot/Touch.Unit@358b283 Remove code to be compatible with MonoTouch (Classic Xamarin.iOS). (#59)
Diff: 9db795d50d..358b283b64
* [src] NUnitLite still needs the XAMCORE_2_0 and __UNIFIED__ defines.
They still have conditional code with those defines:
a977ca5757/NUnitLite-1.0.0/src/framework/Constraints/Numerics.cs (L57)
Co-authored-by: Rolf Bjarne Kvinge <rolf@xamarin.com>
* We require Xcode 6+,, so remove checks for older Xcode versions.
* We require iOS 6+, so remove checks for older iOS versions.
* We don't need to check the Xamarin.iOS version, since we're shipping
together (code checking Xamarin.iOS version is leftover from when the
MSBuild tasks were shipped with Xamarin Studio).
This also allowed us to remove an error (and the corresponding message).
* [src] Update project files to remove XAMCORE_2_0 and __UNIFIED__.
* [src] Update README to remove outdated docs about XAMCORE_2_0.
* [src] Remove Classic code from System.Net.Http.
* [src] Remove Classic code from the ObjCRuntime namespace.
* [src] Remove Classic code from the native types.
* [src] Remove the Classic defines from the makefiles.
* [src] Remove Classic code from the Constants class.
* [src] Remove Classic code from the MonoNativeFunctionWrapper and MonoPInvokeCallback attributes.
* [src] NUnitLite still needs the XAMCORE_2_0 and __UNIFIED__ defines.
They still have conditional code with those defines:
a977ca5757/NUnitLite-1.0.0/src/framework/Constraints/Numerics.cs (L57)
It's not needed, this was a workaround for an issue with the App Store to get
around an ARM64_32 requirement if building with the watchOS 4.3 SDK. The App
Store does not allow shipping apps built with the watchOS 4.3 SDK anymore, so
this workaround is not useful now.
* [msbuild] Unify MtouchArch and XamMacArch into TargetArchitectures.
* [msbuild] Use $(ComputedPlatform) instead of $(_Platform).
They're identical, and this avoids using $(_Platform) before it's defined.
Also rework the class hierarchy a little bit, so that Xamarin.iOS and
Xamarin.Mac are identical:
DetectSigningIdentityTaskBase
└─── iOS/DetectSigningIdentityTaskCore
│ └─── iOS/DetectSigningIdentity
└─── Mac/DetectSigningIdentityTaskCore
│ └─── Mac/DetectSigningIdentity
Alex Soto
Sebastien Pouliot
monojenkins
Manuel de la Pena
Rolf Bjarne Kvinge
Chris Hamons
Emanuel Fernandez Dell'Oca