How to build gas with ASAN/UBSAN?

[Fangrui Song]

On 2020-08-19, Nick Clifton via Binutils wrote:
>Hi Martin,
>
>> One can't do that with CFLAGS="..." ../configure as it would
>> build all .a file with that as well. And test would fail then due to unresolved
>> sanitizer-related symbols.
>
>Err, I use that particular method and it works for me.  You just need to
>add in a definition of LDFLAGS so that the appropriate library is included
>as well.  For example:
>
>  % $BINUTILS_SRCDIR/configure \
>			--enable-targets=all \
>			--enable-64-bit-bfd \
>			CFLAGS='-g -O2 -fsanitize=address' \
>			CXXFLAGS='-g -O2 -fsanitize=address' \
>			LDFLAGS='-ldl' \
>	

Emmm, is LDFLAGS='-fsanitize=address' needed?

See the *link_command section in the output of 
gcc -dumpspecs, -fsanitize=address also affects linking.