[Patch, target] Sort out some issues in config{,/*}/darwin*.h

[Peter O'Gorman]

DISCLAIMER: I am not a maintainer.

On 04/14/2010 11:41 AM, IainS wrote:


>     o macro-ized DSYMUTIL so that we can change it without editing the specs.
>     o Provided a wrapper for the system-supplied dsymutil that allows us to edit out bogus warnings.
>         this is installed in $(libexecdir) . The initial version filters the message that gives us problems
>             like PR43254. 

I think this is not such a bad idea. People building linux -> darwin
cross compilers (At least, I think they exist) currently may have to
edit the specs so that dsymutil is not called, because it is not an open
source project at Apple. Since your wrapper always exits successfully
they shouldn't need to do that anymore... Are you sure that the wrapper
should always exit successfully?

>         (a) Always runs when we are generating an exe - IMO this is more intuitive to the end user - and
>              it side-steps the problem with the existing spec. 

I don't actually agree with this, but don't feel that strongly about it
either.

>     o Filter out -lm and re-apply it where needed.  [I've provided a bolt-hole for anyone who wants to
>        force -lm (-force_lm) at least until we confirm that this is not an issue.] 

There are multpile libraries that are just symlinks to libSystem (libc,
libinfo, libpthread, libdl, for example). It seems odd to treat libm
specially here. If the original problem was a test suite failure, why
not fix the test suite to not add -lm on darwin? Sorry, I know this will
drive you nuts, but I don't get from the PR why you chose this
workaround. If memory serves correctly libm has always been a symlink to
libSystem (or the System framework in 10.0). There is no need to treat
different darwin versions differently here.

> 
>     o fixed darwin10 not to provide no_compact_unwind when building for <10.6. 

Was this actually causing a problem?

Sorry, I didn't spend much time looking at the PRs, I will look more
closely this evening.

Peter