configure: Add --enable-sanitize-address

configure: Add --enable-sanitize-address

--enable-sanitize-address makes sure that all code is compiled with
-fsanitizer=address and all tests run against libasan.

It can be combined with --enable-sanitize-undefined, but not with
--enable-valgrind.

In maintainer mode there is one program that causes leaks, i386_gendis,
so disable leak detection for that program.

One testcase, test_nlist, needs special linker flags, make sure it also
uses -fsanitizer=address when using the address sanitizer.

Signed-off-by: Mark Wielaard <mark@klomp.org>