Merge bitcoin/bitcoin#30488: depends: Fix CMake-generated libevent*.pc files

8c935e625e depends: Fix CMake-generated `libevent*.pc` files (Hennadii Stepanov)

Pull request description:

  Broken out of #30454. This is a backport of the merged upstream PR: https://github.com/libevent/libevent/pull/1622.

  Note that after #29835 we might end up dropping pkg-config and using the installed CMake files directly, but that depends on whether or not enough distros actually ship those files.

  Either way, having fixed up .pc files won't hurt.

ACKs for top commit:
  hebasto:
    ACK 8c935e625e.
  fanquake:
    ACK 8c935e625e

Tree-SHA512: 259c2ad78fb9e90370a7205dc71c40acda1a872f6509435133bc1c4c2c3de57366e80679aa083e13ed85e7966883dc470c0147ee171a2ed0171a18cd5ffc99b3

depends/packages/libevent.mk

@@ -4,6 +4,7 @@ $(package)_download_path=https://github.com/libevent/libevent/releases/download/
 $(package)_file_name=$(package)-$($(package)_version).tar.gz
 $(package)_sha256_hash=92e6de1be9ec176428fd2367677e61ceffc2ee1cb119035037a27d346b0403bb
 $(package)_patches=cmake_fixups.patch
+$(package)_patches+=fix_mingw_link.patch
 $(package)_build_subdir=build
 
 # When building for Windows, we set _WIN32_WINNT to target the same Windows
@@ -21,7 +22,8 @@ define $(package)_set_vars
 endef
 
 define $(package)_preprocess_cmds
-  patch -p1 < $($(package)_patch_dir)/cmake_fixups.patch
+  patch -p1 < $($(package)_patch_dir)/cmake_fixups.patch && \
+  patch -p1 < $($(package)_patch_dir)/fix_mingw_link.patch
 endef
 
 define $(package)_config_cmds