rTorrent: Disable LTO for xmlrpc-c

[stickz]

gcc -pthread   -shared -Wl,-soname,libxmlrpc_util.so.4  asprintf.osh base64.osh error.osh lock_platform.osh lock_pthread.osh lock_none.osh make_printable.osh memblock.osh mempool.osh select.osh sleep.osh string_number.osh time.osh utf8.osh   -o libxmlrpc_util.so.4.60  
0x1892686 internal_error(char const*, ...)
	???:0
0x69cb13 read_cgraph_and_symbols(unsigned int, char const**)
	???:0
0x688832 lto_main()
	???:0
Please submit a full bug report, with preprocessed source (by using -freport-bug).
Please include the complete backtrace with any bug report.
See <file:///usr/share/doc/gcc-12/README.Bugs> for instructions.
lto-wrapper: fatal error: gcc returned 1 exit status
compilation terminated.
/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status