ci: Explicitly specify WiX architecture in packaging jobs

.gitlab/ci/configure_windows_i386_package.cmake

@@ -1,6 +1,9 @@
 # CPack package file name component for this platform.
 set(CPACK_SYSTEM_NAME "windows-i386" CACHE STRING "")
 
+# Tell WiX to package for this architecture.
+set(CPACK_WIX_ARCHITECTURE "x86" CACHE STRING "")
+
 # Use APIs from at most Windows 7
 set(CMAKE_C_FLAGS "-D_WIN32_WINNT=0x601 -DNTDDI_VERSION=0x06010000" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-GR -EHsc -D_WIN32_WINNT=0x601 -DNTDDI_VERSION=0x06010000" CACHE STRING "")

.gitlab/ci/configure_windows_x86_64_package.cmake

@@ -1,6 +1,9 @@
 # CPack package file name component for this platform.
 set(CPACK_SYSTEM_NAME "windows-x86_64" CACHE STRING "")
 
+# Tell WiX to package for this architecture.
+set(CPACK_WIX_ARCHITECTURE "x64" CACHE STRING "")
+
 # Use APIs from at most Windows 7
 set(CMAKE_C_FLAGS "-D_WIN32_WINNT=0x601 -DNTDDI_VERSION=0x06010000" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-GR -EHsc -D_WIN32_WINNT=0x601 -DNTDDI_VERSION=0x06010000" CACHE STRING "")