[Bug target/45258] linkage on -ldl, -lm and -lpthread should be purged from darwin build

[howarth at nitro dot med.uc.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45258

--- Comment #15 from Jack Howarth <howarth at nitro dot med.uc.edu> 2011-01-10 20:27:22 UTC ---
Iain,
   I was referring to the conceptual problems of creating a
version-compare-remove-outfile spec function. For any given OS release there is
a different set of symlinks for libSystem which are visible to the compiler
regardless of the setting of -mmacosx-version-min=. So one would really have to
have version-compare-remove-outfile look only at the running OS version to
decide properly which symlinks are present to prune.