The importance of glibc makes it worthwhile to provide debug
symbols. However, this revealed an issue with separateDebugInfo: it
was indiscriminately adding --build-id to all ld invocations, while in
fact it should only do that for final links. Glibc also uses non-final
("relocatable") links, leading to subsequent failure to apply a build
ID ("Cannot create .note.gnu.build-id section, --build-id
ignored"). So now ld-wrapper.sh only passes --build-id for final
links.
For instance, a binary like libfoo.so will cause a symlink
lib/debug/libfoo.so.debug -> .build-id/<build-ID>.debug to be
created. This is primarily useful for use with eu-addr2line, if you
know the name of a binary and the relative address, but not the build
ID.
You can now pass
separateDebugInfo = true;
to mkDerivation. This causes debug info to be separated from ELF
binaries and stored in the "debug" output. The advantage is that it
enables installing lean binaries, while still having the ability to
make sense of core dumps, etc.
