MDEV-22812 "failed to create symbolic link" during the build

as cmake manual says

  If a sequential execution of multiple commands is required, use multiple
  ``execute_process()`` calls with a single ``COMMAND`` argument.

cmake/mariadb_connector_c.cmake

@@ -43,6 +43,8 @@ ADD_SUBDIRECTORY(libmariadb)
 IF(UNIX)
   INSTALL(CODE "EXECUTE_PROCESS(
                   COMMAND ${CMAKE_COMMAND} -E make_directory ${INSTALL_BINDIR}
+                  WORKING_DIRECTORY \$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX})
+                EXECUTE_PROCESS(
                   COMMAND ${CMAKE_COMMAND} -E create_symlink mariadb_config ${INSTALL_BINDIR}/mariadb-config
                   WORKING_DIRECTORY \$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX})"
           COMPONENT Development)