Merge bitcoin/bitcoin#30903: cmake: Add FindZeroMQ module

915640e191 depends: zeromq: don't install .pc files and remove patches for them (Cory Fields)
6b8a74463b cmake: Add `FindZeroMQ` module (Hennadii Stepanov)

Pull request description:

  This PR introduces the `FindZeroMQ` module, which first attempts to find the `libzmq` library using CMake's `find_package()` and falls back to `pkg_check_modules()` if unsuccessful.

  Addresses https://github.com/bitcoin/bitcoin/issues/30876 for the ZeroMQ package.

ACKs for top commit:
  fanquake:
    ACK 915640e191

Tree-SHA512: 2f17bae21be5d3f280a13425d22f5d1b2e23837a8aaf5ec89c433767509de030a42d598b261e102bdb5b860d8ede98013c124c3d25e081e956d4ee3a81b2584f

CMakeLists.txt

@@ -123,16 +123,7 @@ option(WITH_CCACHE "Attempt to use ccache for compiling." ON)
 
 option(WITH_ZMQ "Enable ZMQ notifications." OFF)
 if(WITH_ZMQ)
-  if(VCPKG_TARGET_TRIPLET)
-    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()
+  find_package(ZeroMQ 4.0.0 MODULE REQUIRED)
 endif()
 
 option(WITH_USDT "Enable tracepoints for Userspace, Statically Defined Tracing." OFF)