Vcpkg macro version for customers (#3909)

* macro version for customers

* remove other macros

* remove variable

tools/AzureVcpkg.cmake

@@ -0,0 +1,51 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# SPDX-License-Identifier: MIT
+
+macro(az_vcpkg_integrate)
+  # AUTO CMAKE_TOOLCHAIN_FILE:
+  # User can call `cmake -DCMAKE_TOOLCHAIN_FILE="path_to_the_toolchain"` as the most specific scenario.
+  # An env var VCPKG_ROOT or VCPKG_INSTALLATION_ROOT can be set to let Azure SDK to set the VCPKG toolchain automatically.
+  # As the last alternative (default case), Azure SDK will automatically clone VCPKG folder and set toolchain from there.
+  if(NOT DEFINED CMAKE_TOOLCHAIN_FILE)
+    if(DEFINED ENV{VCPKG_ROOT})
+      set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake"
+        CACHE STRING "")
+    elseif(DEFINED ENV{VCPKG_INSTALLATION_ROOT})
+      set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_INSTALLATION_ROOT}/scripts/buildsystems/vcpkg.cmake"
+        CACHE STRING "")
+    else()
+      # Set AZURE_SDK_DISABLE_AUTO_VCPKG env var to avoid Azure SDK from cloning and setting VCPKG automatically
+      # This option delegate package's dependencies installation to user.
+      if(NOT DEFINED ENV{AZURE_SDK_DISABLE_AUTO_VCPKG})
+        # GET VCPKG FROM SOURCE
+        # User can set env var AZURE_SDK_VCPKG_COMMIT to pick the VCPKG commit to fetch
+        set(VCPKG_COMMIT_STRING master) # use the last commit from VCPKG to get always the last version available from libs
+
+        if(DEFINED ENV{AZURE_SDK_VCPKG_COMMIT})
+          set(VCPKG_COMMIT_STRING "$ENV{AZURE_SDK_VCPKG_COMMIT}") # default SDK tested commit
+        endif()
+
+        include(FetchContent)
+        FetchContent_Declare(
+          vcpkg
+          GIT_REPOSITORY https://github.com/microsoft/vcpkg.git
+          GIT_TAG ${VCPKG_COMMIT_STRING}
+        )
+        FetchContent_GetProperties(vcpkg)
+
+        # make sure to pull vcpkg only once.
+        if(NOT vcpkg_POPULATED)
+          FetchContent_Populate(vcpkg)
+        endif()
+
+        # use the vcpkg source path
+        set(CMAKE_TOOLCHAIN_FILE "${vcpkg_SOURCE_DIR}/scripts/buildsystems/vcpkg.cmake" CACHE STRING "")
+      endif()
+    endif()
+  endif()
+
+  # enable triplet customization
+  if(DEFINED ENV{VCPKG_DEFAULT_TRIPLET} AND NOT DEFINED VCPKG_TARGET_TRIPLET)
+    set(VCPKG_TARGET_TRIPLET "$ENV{VCPKG_DEFAULT_TRIPLET}" CACHE STRING "")
+  endif()
+endmacro()