- add handle-Werror-return-type.patch
- disable lto, breaks libtool as seen in testsuite

- update to 2.4.7:
- Libtool script now supports (configure-time and runtime) ARFLAGS
variable, which obsoletes AR_FLAGS. This is due to naming conventions
among other *FLAGS and to be consistent with Automake's ARFLAGS.
- Gnulib testsuite is enabled and run during 'make check'.
- Support the Windows version of the Intel C Compiler (icl) in
libtool script.
- Pass '-fsanitize=*' flags for GCC and LLVM, and '-specs=*' for GCC
to linker.
- Pass '-Xassembler=*' and '-Wa,*' flag to compilers and linkers.
- The variable 'FILECMD' with default value of '/usr/bin/file' was used to
replace existing hard coded references to '/usr/bin/file'.
- Add MidnightBSD support.
- Libtool changed ARFLAGS/AR_FLAGS default from 'cru' to 'cr'.
- Do not pass '-pthread' to Solaris linker.
- 'libtool' and 'libtoolize' scripts now use '#! /usr/bin/env sh' shebang.
Previously '#! /bin/sh' was used, which presents challenges for
containerized environments.
- Fix significant slowdown of libtoolize for certain projects (regression
introduced in 2.4.3 release) caused by infinite m4 macro recursion.
- Mitigate the slowdown of libtool script (introduced in v2.4.3) caused by
increased number of calls to '$SED $sed_quote_subst' (bug#20006).
- Properly parse and export TLS symbols on AIX.
- Various bug fixes surrounding use of 'sed'.
- Darwin systems set proper "allow undefined" flag on OSX 11, and
PowerPC 10.5.
- Removed some deprecated tests related to 'Makefile.inc' files.