build: Add a pkg-config file for libbitcoinkernel

Author: TheCharlatan

libbitcoinkernel.pc.in

@@ -0,0 +1,11 @@
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
+includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+
+Name: @PACKAGE_NAME@ kernel library
+Description: Experimental library for the Bitcoin Core validation engine.
+Version: @PACKAGE_VERSION@
+Libs: -L${libdir} -lbitcoinkernel
+Libs.private: -L${libdir} @LIBS_PRIVATE@
+Cflags: -I${includedir}

src/kernel/CMakeLists.txt

@@ -119,11 +119,19 @@ if(NOT BUILD_SHARED_LIBS)
   set(all_kernel_static_link_libs "")
   get_target_static_link_libs(bitcoinkernel all_kernel_static_link_libs)
 
+  # LIBS_PRIVATE is substituted in the pkg-config file.
+  set(LIBS_PRIVATE "")
   foreach(lib ${all_kernel_static_link_libs})
     install(TARGETS ${lib} ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    string(APPEND LIBS_PRIVATE " -l${lib}")
   endforeach()
+
+  string(STRIP "${LIBS_PRIVATE}" LIBS_PRIVATE)
 endif()
 
+configure_file(${PROJECT_SOURCE_DIR}/libbitcoinkernel.pc.in ${PROJECT_BINARY_DIR}/libbitcoinkernel.pc @ONLY)
+install(FILES ${PROJECT_BINARY_DIR}/libbitcoinkernel.pc DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
+
 include(GNUInstallDirs)
 install(TARGETS bitcoinkernel
   RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}