Update FindVulkan.cmake to cross-compile for Windows/Windows on ARM64 (KhronosGroup#1490)

* Remove vendored downstream version of `FindVulkan.cmake`

Let CMake use its own bundled version of this module. It is more maintained and has some quality of life fixed, most notably cross-compilation on Windows(ARM64/Intel).

See KhronosGroup#1489 for more context about this change.

* bldsys/toolchain: introduce `ios.cmake` toolchain file

As per upstream CMake recommendations, configure iOS targets using a
toolchain file.

* build.yml: update workflow for iOS CI to use ios toolchain file

Move all the variables that were passed through command line here, as per
CMake upstream recommendation.

* app/CMakeLists.txt: compute `Vulkan_Target_SDK`

Removing downstream vendored version of `FindVulkan.cmake` caused this
variable to disappear. Compute it again where it is needed.

KhronosGroup#1490 (comment)
for the full discussion.

* Revert "Remove vendored downstream version of `FindVulkan.cmake`"

This reverts commit 1a672f7.

* Revert "bldsys/toolchain: introduce `ios.cmake` toolchain file"

This reverts commit 6f1680f.

* Revert "build.yml: update workflow for iOS CI to use ios toolchain file"

This reverts commit 265d313.

* bldsys/cmake/module/FindVulkan.cmake: Backport upstream changes

Backport these patches into our downstream `FindVulkan` CMake module:

5e1440302a FindVulkan: Add support for cross-compiling between Windows x64/ARM64
f9a09f76f3 FindVulkan: Drop support for 32-bit SDK on Windows
b40740f28a FindVulkan: Do not search bin directories for libraries
947adbba91 FindVulkan: Use ENV{VULKAN_SDK} only if it exists

This allows proper libraries discovery of Vulkan Libraries on Windows,
both for x86_64 and ARM64 targets.

Co-Authored-By: Brad King <brad.king@kitware.com>
Tested-By: Giancane, Francesco <fgiancan@qti.qualcomm.com>

* Fix wrong copyright years. Add license attributions for my changes.

* app/CMakeLists.txt: restore file to its original content

Changes are addressed in KhronosGroup#1500.

* bldsys/cmake/module/FindVulkan.cmake: restore if(APPLE) branch

As per request on the discussion thread, let's just import the changes
required to build Vulkan Samples on Windows/Windows on ARM64.

---------

Co-authored-by: Brad King <brad.king@kitware.com>

Author: fgiancane8

bldsys/cmake/module/FindVulkan.cmake

@@ -1,4 +1,5 @@
-# Updates for iOS Copyright (c) 2024, Holochip Inc.
+# Updates for iOS Copyright (c) 2024-2026, Holochip Inc.
+# Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
 # Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
 # file Copyright.txt or https://cmake.org/licensing for details.
 
@@ -263,40 +264,57 @@ endif()
 
 if(WIN32)
     set(_Vulkan_library_name vulkan-1)
-    set(_Vulkan_hint_include_search_paths
-            "$ENV{VULKAN_SDK}/include"
-    )
-    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
-        set(_Vulkan_hint_executable_search_paths
-                "$ENV{VULKAN_SDK}/bin"
-        )
-        set(_Vulkan_hint_library_search_paths
-                "$ENV{VULKAN_SDK}/lib"
-                "$ENV{VULKAN_SDK}/bin"
-        )
-    else()
-        set(_Vulkan_hint_executable_search_paths
-                "$ENV{VULKAN_SDK}/bin32"
-                "$ENV{VULKAN_SDK}/bin"
-        )
-        set(_Vulkan_hint_library_search_paths
-                "$ENV{VULKAN_SDK}/lib32"
-                "$ENV{VULKAN_SDK}/bin32"
-                "$ENV{VULKAN_SDK}/lib"
-                "$ENV{VULKAN_SDK}/bin"
-        )
-    endif()
 else()
     set(_Vulkan_library_name vulkan)
+endif()
+set(_Vulkan_hint_include_search_paths "")
+set(_Vulkan_hint_executable_search_paths "")
+set(_Vulkan_hint_library_search_paths "")
+
+if(DEFINED ENV{VULKAN_SDK} AND IS_DIRECTORY "$ENV{VULKAN_SDK}")
     set(_Vulkan_hint_include_search_paths
-            "$ENV{VULKAN_SDK}/include"
+        "$ENV{VULKAN_SDK}/include"
     )
     set(_Vulkan_hint_executable_search_paths
-            "$ENV{VULKAN_SDK}/bin"
+        "$ENV{VULKAN_SDK}/bin"
     )
+    if(WIN32)
+        # Detect the target architecture from one of:
+        # - the C++ compiler,
+        # - the C compiler,
+        # - the VS generator,
+        # - the command-line environment,
+        # - fallback to CMAKE_SYSTEM_PROCESSOR.
+        if(CMAKE_CXX_COMPILER_LOADED AND CMAKE_CXX_COMPILER_ARCHITECTURE_ID)
+            set(_Vulkan_arch_name "${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}")
+        elseif(CMAKE_C_COMPILER_LOADED AND CMAKE_C_COMPILER_ARCHITECTURE_ID)
+            set(_Vulkan_arch_name "${CMAKE_C_COMPILER_ARCHITECTURE_ID}")
+        elseif(CMAKE_VS_PLATFORM_NAME)
+            set(_Vulkan_arch_name "${CMAKE_VS_PLATFORM_NAME}")
+        elseif(DEFINED ENV{VSCMD_ARG_TGT_ARCH})
+            set(_Vulkan_arch_name "$ENV{VSCMD_ARG_TGT_ARCH}")
+        elseif(CMAKE_SYSTEM_PROCESSOR)
+            set(_Vulkan_arch_name "${CMAKE_SYSTEM_PROCESSOR}")
+        endif()
+        # The Vulkan SDK may provide arch-specific directories for cross-compiling.
+        if(_Vulkan_arch_name MATCHES "^(ARM64|arm64|aarch64)" AND IS_DIRECTORY "$ENV{VULKAN_SDK}/lib-arm64")
+            # On X64 hosts the Vulkan SDK provides `-arm64` dirs for cross-compiling to ARM64.
+            set(_Vulkan_arch_suffix "-arm64")
+        elseif(_Vulkan_arch_name MATCHES "^(X64|x64|x86_64)" AND IS_DIRECTORY "$ENV{VULKAN_SDK}/lib-x64")
+            # On ARM64 hosts the Vulkan SDK provides `-x64` dirs for cross-compiling to x64.
+            set(_Vulkan_arch_suffix "-x64")
+        else()
+            # Otherwise assume we are compiling for the host.
+            set(_Vulkan_arch_suffix "")
+        endif()
+        unset(_Vulkan_arch_name)
+    else()
+        set(_Vulkan_arch_suffix "")
+    endif()
     set(_Vulkan_hint_library_search_paths
-            "$ENV{VULKAN_SDK}/lib"
+        "$ENV{VULKAN_SDK}/lib${_Vulkan_arch_suffix}"
     )
+    unset(_Vulkan_arch_suffix)
 endif()
 if(APPLE AND DEFINED Vulkan_Target_SDK)
     list(APPEND _Vulkan_hint_include_search_paths