windows: Make cmake use vcpkg toolchain file by default

windows1809/base/Dockerfile

@@ -47,3 +47,4 @@ RUN $vcpkg_dir = 'C:/vcpkg'; \
     git checkout c05eb1ab83ddb9d4799fb9f3cd10bb385f05469b; \
     ./scripts/bootstrap.ps1; \
     [Environment]::SetEnvironmentVariable('VCPKG_DIR', "\"$vcpkg_dir\"", [EnvironmentVariableTarget]::Machine);
+ADD powershell/vcpkg-cmake.ps1 /Windows/System32/WindowsPowerShell/v1.0/profile.d/vcpkg-cmake.ps1

windows1809/base/powershell/vcpkg-cmake.ps1

+# SPDX-License-Identifier: MIT
+
+#
+# Executes CMake with vcpkg toolchain file
+#
+function vcpkg-cmake {
+	Must-Run "Program Files/CMake/bin/cmake.exe" '-DCMAKE_TOOLCHAIN_FILE=/vcpkg/scripts/buildsystems/vcpkg.cmake'
+}
+
+# Use vcpkg-cmake by default
+Set-Alias -Name cmake -Value vcpkg-cmake