add ZMQ_PREFIX to $RPATH by default

old setup.py used to try to do this

CMakeLists.txt

@@ -18,6 +18,7 @@ endif()
 # legacy pyzmq env options, no PYZMQ_ prefix
 set(ZMQ_PREFIX "auto" CACHE STRING "libzmq installation prefix or 'bundled'")
 option(ZMQ_DRAFT_API "whether to build the libzmq draft API" OFF)
+option(PYZMQ_LIBZMQ_RPATH "Add $ZMQ_PREFIX/lib to $RPATH (true by default). Set to false if libzmq will be bundled or relocated and RPATH is handled separately" ON)
 
 # anything new should start with PYZMQ_
 option(PYZMQ_LIBZMQ_NO_BUNDLE "Prohibit building bundled libzmq. Useful for repackaging, to allow default search for libzmq and requiring it to succeed." OFF)
@@ -37,7 +38,7 @@ endif()
 # get options from env
 
 # handle booleans
-foreach(_optname ZMQ_DRAFT_API PYZMQ_NO_BUNDLE)
+foreach(_optname ZMQ_DRAFT_API PYZMQ_NO_BUNDLE PYZMQ_LIBZMQ_RPATH)
   if (DEFINED ENV{${_optname}})
     if ("$ENV{${_optname}}" STREQUAL "1" OR "$ENV{${_optname}}" STREQUAL "ON")
       set(${_optname} TRUE)
@@ -115,6 +116,12 @@ if (ZMQ_PREFIX STREQUAL "auto")
         set(ZeroMQ_FOUND TRUE)
         set(libzmq_target "PkgConfig::libzmq")
         message(CHECK_PASS "found: -L${libzmq_LIBRARY_DIRS} -l${libzmq_LIBRARIES}")
+        if (PYZMQ_LIBZMQ_RPATH)
+          foreach(LIBZMQ_LIB_DIR IN LISTS libzmq_LIBRARY_DIRS)
+            message(STATUS "  Adding ${LIBZMQ_LIB_DIR} to RPATH, set PYZMQ_LIBZMQ_RPATH=OFF if this is not what you want.")
+            list(APPEND CMAKE_INSTALL_RPATH "${LIBZMQ_LIB_DIR}")
+          endforeach()
+        endif()
       else()
         message(CHECK_FAIL "no")
       endif()
@@ -130,6 +137,12 @@ if (ZMQ_PREFIX STREQUAL "auto")
     if (LIBZMQ_LIBRARY AND LIBZMQ_INCLUDE_DIR)
       set(ZeroMQ_FOUND TRUE)
       message(CHECK_PASS "${LIBZMQ_LIBRARY}")
+      # NOTE: we _could_ set RPATH here. Should we? Unclear.
+      if (PYZMQ_LIBZMQ_RPATH)
+        get_filename_component(LIBZMQ_LIB_DIR "${LIBZMQ_LIBRARY}" DIRECTORY)
+        message(STATUS "  Adding ${LIBZMQ_LIB_DIR} to RPATH, set PYZMQ_LIBZMQ_RPATH=OFF if this is not what you want.")
+        list(APPEND CMAKE_INSTALL_RPATH "${LIBZMQ_LIB_DIR}")
+      endif()
     endif()
   endif()
 
@@ -157,6 +170,11 @@ elseif (NOT ZMQ_PREFIX STREQUAL "bundled")
   )
   if (LIBZMQ_LIBRARY AND LIBZMQ_INCLUDE_DIR)
     message(CHECK_PASS "${LIBZMQ_LIBRARY}")
+    if (PYZMQ_LIBZMQ_RPATH)
+      # add prefix to RPATH
+      message(STATUS "  Adding ${ZMQ_PREFIX}/lib to RPATH, set PYZMQ_LIBZMQ_RPATH=OFF if this is not what you want.")
+      list(APPEND CMAKE_INSTALL_RPATH "${ZMQ_PREFIX}/lib")
+    endif()
   else()
     message(CHECK_FAIL "no")
     message(FATAL_ERROR "libzmq not found in ZMQ_PREFIX=${ZMQ_PREFIX}")

pyproject.toml

@@ -158,6 +158,7 @@ musllinux-x86_64-image = "musllinux_1_1"
 
 [tool.cibuildwheel.linux.environment]
 ZMQ_PREFIX = "/usr/local"
+PYZMQ_LIBZMQ_RPATH = "OFF"
 CFLAGS = "-Wl,-strip-all"
 CXXFLAGS = "-Wl,-strip-all"
 
@@ -166,6 +167,7 @@ before-all = "bash tools/install_libzmq.sh"
 
 [tool.cibuildwheel.macos.environment]
 ZMQ_PREFIX = "/tmp/zmq"
+PYZMQ_LIBZMQ_RPATH = "OFF"
 MACOSX_DEPLOYMENT_TARGET = "10.9"
 
 [tool.cibuildwheel.windows]