Derive debian13 library dir and Rust package from the architecture

- Make the libevent install patch take CMAKE_INSTALL_LIBDIR instead of
  hardcoding lib/x86_64-linux-gnu, and rename it to
  libevent-libdir-install.patch.
- Replace every hardcoded x86_64-linux-gnu in the debian13 Dockerfile with
  $(gcc -dumpmachine).
- Download the Rust tarball for `uname -m` and expose it to the Dockerfiles
  as the architecture-neutral rust-1.99.1.tar.xz (a hard link refreshed on
  every run), because podman cannot expand ARG in a --mount source.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

debian13/libevent-libdir-install.patch

@@ -0,0 +1,65 @@
+--- a/cmake/AddEventLibrary.cmake
++++ b/cmake/AddEventLibrary.cmake
+@@ -31,7 +31,7 @@
+     configure_file("lib${LIB_NAME}.pc.in" "lib${LIB_NAME}.pc" @ONLY)
+     install(
+         FILES "${CMAKE_CURRENT_BINARY_DIR}/lib${LIB_NAME}.pc"
+-        DESTINATION "${CMAKE_INSTALL_PREFIX}/lib/pkgconfig"
++        DESTINATION "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}/pkgconfig"
+     )
+ endmacro()
+ 
+@@ -40,9 +40,9 @@
+ macro(export_install_target TYPE LIB_NAME OUTER_INCLUDES)
+     if("${LIB_NAME}" STREQUAL "event")
+         install(TARGETS "${LIB_NAME}_${TYPE}"
+-            LIBRARY DESTINATION "lib" COMPONENT lib
+-            ARCHIVE DESTINATION "lib" COMPONENT lib
+-            RUNTIME DESTINATION "lib" COMPONENT lib
++            LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT lib
++            ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT lib
++            RUNTIME DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT lib
+             COMPONENT dev
+         )
+     else()
+@@ -67,9 +67,9 @@
+         )
+         install(TARGETS "${LIB_NAME}_${TYPE}"
+             EXPORT LibeventTargets-${TYPE}
+-            LIBRARY DESTINATION "lib" COMPONENT lib
+-            ARCHIVE DESTINATION "lib" COMPONENT lib
+-            RUNTIME DESTINATION "lib" COMPONENT lib
++            LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT lib
++            ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT lib
++            RUNTIME DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT lib
+             COMPONENT dev
+         )
+     endif()
+@@ -181,7 +181,7 @@
+         if (NOT WIN32)
+             install(FILES
+                 "$<TARGET_FILE_DIR:${LIB_NAME}_shared>/${LIB_LINK_NAME}"
+-                DESTINATION "lib"
++                DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+                 COMPONENT lib)
+         endif()
+     endif()
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -946,6 +946,7 @@
+ #
+ # Create the libraries.
+ #
++include(GNUInstallDirs)
+ include(AddEventLibrary)
+ add_event_library(event_core SOURCES ${SRC_CORE})
+ add_event_library(event_extra
+@@ -1453,7 +1454,7 @@
+ #
+ 
+ set(EVENT_INSTALL_CMAKE_DIR
+-    "${CMAKE_INSTALL_PREFIX}/lib/cmake/libevent")
++    "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}/cmake/libevent")
+ 
+ export(PACKAGE libevent)
+