utils: improve android swift-corelibs-foundation support

Adjust the build invocation for swift-corelibs-foundation to account for
changes required for building for android after re-coring the library.
We use the SDKRoot to find the necessary libraries.

Author: compnerd

utils/build.ps1

@@ -269,6 +269,7 @@ $AndroidARM64 = @{
   CMakeName = "aarch64";
   LLVMName = "aarch64";
   LLVMTarget = "aarch64-unknown-linux-android$AndroidAPILevel";
+  ShortName = "arm64";
   BuildID = 400;
   BinaryCache = "$BinaryCache\aarch64";
   PlatformInstallRoot = "$BinaryCache\arm64\Android.platform";
@@ -283,6 +284,7 @@ $AndroidARMv7 = @{
   CMakeName = "armv7-a";
   LLVMName = "armv7";
   LLVMTarget = "armv7-unknown-linux-androideabi$AndroidAPILevel";
+  ShortName = "armv7";
   BuildID = 500;
   BinaryCache = "$BinaryCache\armv7";
   PlatformInstallRoot = "$BinaryCache\armv7\Android.platform";
@@ -297,6 +299,7 @@ $AndroidX86 = @{
   CMakeName = "i686";
   LLVMName = "i686";
   LLVMTarget = "i686-unknown-linux-android$AndroidAPILevel";
+  ShortName = "i686";
   BuildID = 600;
   BinaryCache = "$BinaryCache\i686";
   PlatformInstallRoot = "$BinaryCache\x86\Android.platform";
@@ -311,6 +314,7 @@ $AndroidX64 = @{
   CMakeName = "x86_64";
   LLVMName = "x86_64";
   LLVMTarget = "x86_64-unknown-linux-android$AndroidAPILevel";
+  ShortName = "x86_64";
   BuildID = 700;
   BinaryCache = "$BinaryCache\x86_64";
   PlatformInstallRoot = "$BinaryCache\x64\Android.platform";
@@ -1056,36 +1060,44 @@ function Build-CMakeProject {
       }
       TryAdd-KeyValue $Defines CMAKE_Swift_COMPILER_TARGET $Arch.LLVMTarget.Replace("$AndroidAPILevel", "")
       if ($UseBuiltCompilers.Contains("Swift")) {
-        if ($SwiftSDK -ne "") {
-          $SwiftArgs += @("-sdk", $SwiftSDK)
-        } else {
-          $RuntimeBinaryCache = Get-TargetProjectBinaryCache $Arch Runtime
-          $SwiftResourceDir = "${RuntimeBinaryCache}\lib\swift"
-
-          switch ($Platform) {
-            Windows {
+        $RuntimeBinaryCache = Get-TargetProjectBinaryCache $Arch Runtime
+        $SwiftResourceDir = "${RuntimeBinaryCache}\lib\swift"
+
+        switch ($Platform) {
+          Windows {
+            if ($SwiftSDK -ne "") {
+              $SwiftArgs += @("-sdk", $SwiftSDK)
+            } else {
               $SwiftArgs += @(
                 "-vfsoverlay", "$RuntimeBinaryCache\stdlib\windows-vfs-overlay.yaml",
                 "-strict-implicit-module-context",
                 "-Xcc", "-Xclang", "-Xcc", "-fbuiltin-headers-in-system-modules"
               )
+              $SwiftArgs += @("-resource-dir", "$SwiftResourceDir")
+              $SwiftArgs += @("-L", "$SwiftResourceDir\$($Platform.ToString().ToLowerInvariant())")
             }
-            Android {
-              $androidNDKPath = Get-AndroidNDKPath
+          }
+          Android {
+            $androidNDKPath = Get-AndroidNDKPath
+            if ($SwiftSDK -ne "") {
+              $SwiftArgs += @("-sdk", $SwiftSDK)
+              $SwiftArgs += @("-sysroot", "$androidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\sysroot")
+            } else {
               $SwiftArgs += @("-sdk", "$androidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\sysroot")
-              $SwiftArgs += @(
-                "-Xclang-linker", "-target",
-                "-Xclang-linker", $Arch.LLVMTarget,
-                "-Xclang-linker", "--sysroot",
-                "-Xclang-linker", "$androidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\sysroot",
-                "-Xclang-linker", "-resource-dir",
-                "-Xclang-linker", "$androidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\lib\clang\17"
-              )
+              $SwiftArgs += @("-resource-dir", "$SwiftResourceDir")
+              $SwiftArgs += @("-L", "$SwiftResourceDir\$($Platform.ToString().ToLowerInvariant())")
             }
+            $SwiftArgs += @(
+              "-Xclang-linker", "-target",
+              "-Xclang-linker", $Arch.LLVMTarget,
+              "-Xclang-linker", "--sysroot",
+              "-Xclang-linker", "$androidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\sysroot",
+              "-Xclang-linker", "-resource-dir",
+              "-Xclang-linker", "$androidNDKPath\toolchains\llvm\prebuilt\windows-x86_64\lib\clang\17"
+            )
           }
-          $SwiftArgs += @("-resource-dir", "$SwiftResourceDir")
-          $SwiftArgs += @("-L", "$SwiftResourceDir\$($Platform.ToString().ToLowerInvariant())")
         }
+
       } else {
         $SwiftArgs += @("-sdk", (Get-PinnedToolchainSDK))
       }
@@ -1775,6 +1787,12 @@ function Build-Foundation([Platform]$Platform, $Arch, [switch]$Test = $false) {
       $Targets = @("default")
       $InstallPath = "$($Arch.SDKInstallRoot)\usr"
 
+      $SDKRoot = if ($Platform -eq "Windows") {
+        ""
+      } else {
+        (Get-Variable "${Platform}$($Arch.ShortName)" -ValueOnly).SDKInstallRoot
+      }
+
       Build-CMakeProject `
         -Src $SourceCache\swift-corelibs-foundation `
         -Bin $FoundationBinaryCache `