Meta: Add workaround for CMake 4.0 policy minimum changes

In CMake 4.0, having a minimum policy version set to less than 3.5 is
a hard error at configure time. Add an override until the issue can be
resolved in vcpkg itself.

Meta/CMake/vcpkg/generate_vcpkg_toolchain_variables.cmake

@@ -17,6 +17,11 @@ if (LINUX AND NOT LAGOM_USE_LINKER)
     string(APPEND EXTRA_VCPKG_VARIABLES "set(ENV{LDFLAGS} -Wl,-z,noseparate-code)\n")
 endif()
 
+# Temporary workaround until a version of vcpkg with https://github.com/microsoft/vcpkg/pull/44712 is released
+if (CMAKE_VERSION VERSION_GREATER_EQUAL "4.0")
+    string(APPEND EXTRA_VCPKG_VARIABLES "set(ENV{CMAKE_POLICY_VERSION_MINIMUM} 3.5)\n")
+endif()
+
 file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/build-vcpkg-variables.cmake" "${EXTRA_VCPKG_VARIABLES}")
 
 # Munge the VCPKG_TRIPLET to correspond to the right one for our presets