cmake: Add FindZeroMQ module

CMakeLists.txt

@@ -133,16 +133,7 @@ endif()
 
 option(WITH_ZMQ "Enable ZMQ notifications." OFF)
 if(WITH_ZMQ)
-  if(VCPKG_TARGET_TRIPLET)
+  find_package(ZeroMQ 4.0.0 MODULE REQUIRED)
-    find_package(ZeroMQ CONFIG REQUIRED)
-  else()
-    # The ZeroMQ project has provided config files since v4.2.2.
-    # However, mainstream distributions do not yet provide CMake
-    # config files for ZeroMQ packages. If they do in the future,
-    # find_package(ZeroMQ) may be used instead.
-    find_package(PkgConfig REQUIRED)
-    pkg_check_modules(libzmq REQUIRED IMPORTED_TARGET libzmq>=4)
-  endif()
 endif()
 
 option(WITH_USDT "Enable tracepoints for Userspace, Statically Defined Tracing." OFF)

cmake/module/FindZeroMQ.cmake

@@ -0,0 +1,41 @@
+# Copyright (c) 2024-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+#[=======================================================================[
+FindZeroMQ
+----------
+
+Finds the ZeroMQ headers and library.
+
+This is a wrapper around find_package()/pkg_check_modules() commands that:
+ - facilitates searching in various build environments
+ - prints a standard log message
+
+#]=======================================================================]
+
+include(FindPackageHandleStandardArgs)
+find_package(ZeroMQ ${ZeroMQ_FIND_VERSION} NO_MODULE QUIET)
+if(ZeroMQ_FOUND)
+  find_package_handle_standard_args(ZeroMQ
+    REQUIRED_VARS ZeroMQ_DIR
+    VERSION_VAR ZeroMQ_VERSION
+  )
+  if(TARGET libzmq)
+    add_library(zeromq ALIAS libzmq)
+  elseif(TARGET libzmq-static)
+    add_library(zeromq ALIAS libzmq-static)
+  endif()
+  mark_as_advanced(ZeroMQ_DIR)
+else()
+  find_package(PkgConfig REQUIRED)
+  pkg_check_modules(libzmq QUIET
+    IMPORTED_TARGET
+    libzmq>=${ZeroMQ_FIND_VERSION}
+  )
+  find_package_handle_standard_args(ZeroMQ
+    REQUIRED_VARS libzmq_LIBRARY_DIRS
+    VERSION_VAR libzmq_VERSION
+  )
+  add_library(zeromq ALIAS PkgConfig::libzmq)
+endif()

src/zmq/CMakeLists.txt

@@ -12,13 +12,10 @@ add_library(bitcoin_zmq STATIC EXCLUDE_FROM_ALL
 target_compile_definitions(bitcoin_zmq
   INTERFACE
     ENABLE_ZMQ=1
-  PRIVATE
-    $<$<AND:$<PLATFORM_ID:Windows>,$<CXX_COMPILER_ID:GNU>>:ZMQ_STATIC>
 )
 target_link_libraries(bitcoin_zmq
   PRIVATE
     core_interface
     univalue
-    $<TARGET_NAME_IF_EXISTS:libzmq>
+    zeromq
-    $<TARGET_NAME_IF_EXISTS:PkgConfig::libzmq>
 )