[Xamarin.Android.Build.Tasks] Quote Aot Paths (again)

[dellis1972]

Fixes #5964

In commit accc846 we missed a few paths which might need to be quoted in order to handle
spaces in the paths. As a result users are seeing errors like the one below.

2021-05-28T22:15:09.3191452Z   [aot-compiler stdout] Executing the native linker: "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE" -Bsymbolic -shared -o obj\Release\110\aot\armeabi-v7a\libaot-Xamarin.AndroidX.CardView.dll.so.tmp "obj\Release\110\aot\armeabi-v7a\Xamarin.AndroidX.CardView.dll\temp-llvm.o" obj\Release\110\aot\armeabi-v7a\Xamarin.AndroidX.CardView.dll\temp.s.o -LC:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x -LC:\Program Files (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib -LC:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\..\sysroot\usr\lib\arm-linux-androideabi "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x\libgcc.a" "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib\libc.so" "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib\libm.so"
2021-05-28T22:15:09.3195848Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open Files: No such file or directory
2021-05-28T22:15:09.3197593Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x: No such file or directory
2021-05-28T22:15:09.3199375Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open Files: No such file or directory
2021-05-28T22:15:09.3200935Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib: No such file or directory
2021-05-28T22:15:09.3202549Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open Files: No such file or directory
2021-05-28T22:15:09.3204244Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\..\sysroot\usr\lib\arm-linux-androideabi: No such file or directory
2021-05-28T22:15:09.3205865Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -lunwind
2021-05-28T22:15:09.3207138Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -lcompiler_rt-extras
2021-05-28T22:15:09.3208785Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -lgcc_real
2021-05-28T22:15:09.3210086Z   [aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -ldl

So lets quote ALL the things. Also update the Aot Unit tests to use Sdk/Ndk paths with spaces in them. We do this
by creating a symlink to the existing Sdk/Ndk directories in the Unit Test temp directory.
This highlighted a bug in the MacOS ndk were the aarch64-linux-android21-clang script would return the following
error

usage: dirname path

This is because the bash script on MacOS does not support paths with spaces... very similar to many of the .bat files
on Windows. So for now we are disabling the use of Sdk/Ndk paths with spaces on non windows platforms until a
fix can be found. These changes should allow windows users to use Aot again though since its mostly windows users
who have the Sdk/Ndk directories in locations where spaces are in the path.

[jonathanpeppers]

I think we could make a test that uses this to create a symbolic link to the NDK:

https://github.com/xamarin/xamarin-android/blob/main/tools/xabuild/SymbolicLink.cs

And use a path with spaces.

Did we change something that broke this?

[dellis1972]

This was caused by https://github.com/xamarin/xamarin-android/pull/5475/files#diff-d4dcca33896738b8e073a8fde94253a72f9b76cf0923179cb06a94a8db740f41R386

[dellis1972]

Might also fix #5764

[jonathanpeppers]

Tested this locally, and it seems to be working:

Task Aot 26.276s
...
AndroidNdkDirectory = C:\src\xamarin-android\bin\TestDebug\temp\SDK Ümläüts\ndk\
EnableLLVM = True
...
Build succeeded.
Duration = 36.598 s

[jonpryor]

Fixes: https://github.com/xamarin/xamarin-android/issues/5964

Context: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1336413

Context: accc846e35ccc2b21e2a472d51ab58ed0682643a
Context: 8923c11b04ef52bbf238955cefdb9995c5b5ed38
Context: 9b928f9f5fb097d8c98b7a389dbfa76846ed7ed3

Customers report that when building a project:

 1. On Windows
 2. With Visual Studio 16.10, *not* 16.9 or earlier
 3. In Release configuration
 4. With `$(AotAssemblies)`=True *and* `$(EnableLLVM)`=True
 5. With the NDK installed into a directory containing spaces

then the app fails to build:

	[aot-compiler stdout] Executing the native linker: "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE" -Bsymbolic -shared -o obj\Release\110\aot\armeabi-v7a\libaot-Xamarin.AndroidX.CardView.dll.so.tmp "obj\Release\110\aot\armeabi-v7a\Xamarin.AndroidX.CardView.dll\temp-llvm.o" obj\Release\110\aot\armeabi-v7a\Xamarin.AndroidX.CardView.dll\temp.s.o -LC:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x -LC:\Program Files (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib -LC:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\..\sysroot\usr\lib\arm-linux-androideabi "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x\libgcc.a" "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib\libc.so" "C:\Program Files (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib\libm.so"
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open Files: No such file or directory
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x: No such file or directory
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open Files: No such file or directory
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open (x86)\Android\android-sdk\ndk-bundle\platforms\android-21\arch-arm\usr\lib: No such file or directory
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open Files: No such file or directory
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot open (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\..\sysroot\usr\lib\arm-linux-androideabi: No such file or directory
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -lunwind
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -lcompiler_rt-extras
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -lgcc_real
	[aot-compiler stderr] C:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\arm-linux-androideabi-ld.EXE: error: cannot find -ldl

The *immediate* cause of the failure is path quoting: the
`arm-linux-androideabi-ld.EXE` invocation contains:

	-LC:\Program Files (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x 

This value is not quoted, and parts of that path are seen in the
error messages:

	error: cannot open Files: No such file or directory
	error: cannot open (x86)\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x: No such file or directory

"So", we say, "let's quote those paths!"

Update the `<Aot/>` task so that *all* the paths passed to Mono in the
`ld-flags` parameter are quoted, not just `libgcc.a`, `libc.so`, and
`libm.so`.  This fixes the above linker invocation.

Additionally, update the `AotTests` test fixture so that when the
tests run on Windows, Android SDK and NDK installation locations are
symlinked into a directory containing spaces and Ümläüts.
These "SDK Ümläüts" directories are then used by the unit tests.
This helps *ensure* that we're appropriately wrapping paths, by
ensuring that the SDK & NDK are in a directory with spaces.

We don't (yet) use these "SDK Ümläüts" for macOS unit tests because
the Android NDK `aarch64-linux-android21-clang` & related scripts
don't properly quote paths either:

	`dirname $0`/clang --target=aarch64-linux-android21 "$@"

which means an `SDK Ümläüts/ndk/…/aarch64-linux-android21-clang`
invocation fails with:

	usage: dirname path

TODO: address this shortcoming, by skipping
`aarch64-linux-android21-clang` and instead directly executing
`…/clang --target=aarch64-linux-android21`.

---

…except.  Except.

Except a lot of this doesn't *quite* make sense.

Lack of path quoting, *in and of itself*, is readily explainable and
plainly observed here.

The problem is that `ld-flags` construction hasn't changed much since
commit 8923c11b, in 2019-Sep-4 (21 months ago!), in particular the
`libs.Add($"-L{toolchainLibDir}")` and
`libs.Add($"-L{androidLibPath}")` statements.  Commit 9b928f9f
changed this slightly, wrapping `libgcc.a`/etc. with quotes, but did
*not* touch `toolchainLibDir` or `androidLibPath`, both of which are
responsible for the `-L…` values implicated in the above errors.

Thus, we are getting customer complaints related to AOT path quoting
when none of the relevant code has changed between d16-9 and d16-10.
The only AOT-related change is accc846e, which added support to pass
the new-to-mono `ld-name` option for AOT.  `ld-name` *doesn't*
involve the directory name, and thus doesn't seem relevant here.

We *know* `ld-flags` is *involved*, because updating the `ld-flags`
value we provide to mono fixes the issue.  However, is this a
*fix* or a *workaround*? ¯\_(ツ)_/¯ 

Additionally, *why* did this start failing with d16-10?

  * Xamarin.Android change that isn't "obviously" related to AOT?

  * Mono changes?
    https://github.com/mono/mono/compare/5e9cb6d1c1de430965312927d5aed7fcb27bfa73...b4a385816ed4f1398d0184c38f19f560e868fd80

    There are no "obvious" changes in behavior related to `ld-flags`
    or `ld_flags`, nor anything else "obvious" that would alter
    behavior.

  * "Environment" change, e.g. in d16-9 the NDK was installed into a
    directory that lacked spaces, while in d16-10 the NDK is now
    installed into a directory containing spaces?

    There *may* be something here, but it's hard to say.
    The [GitHub Actions Microsoft Windows Server 2019 Datacenter][0]
    environment lists the NDK installation location as a path with
    *no* spaces:

        C:\Android\android-sdk\ndk\22.1.7171670

    Yet we have a report of the same "path quoting" failure happening
    ["on Github actions"][1], referencing a path that differs from
    the documented path:

        C:\Program Files (x86)\Android\android-sdk\ndk\21.4.7075529\toolchains\llvm\prebuilt\windows-x86_64\lib\gcc\arm-linux-androideabi\4.9.x

    Why does the documentation mention `C:\Android`, while
    `C:\Program Files (x86)` is used?

    Did our NDK path lookup logic change?

We don't currently know why things started blowing up in
Visual Studio 16.10.  Investigation is ongoing.

[0]: https://github.com/actions/virtual-environments/blob/2823a3cb6a62cc74961527bdf7623b4b9afb4107/images/win/Windows2019-Readme.md
[1]: https://github.com/xamarin/xamarin-android/issues/5964#issuecomment-853068001