There was an overload of fabs for std::complex in TR1 and in some C++0x
drafts, but it was removed from the working draft by LWG 595.
Since we've been providing it for decades we should deprecate it before
removing it.
libstdc++-v3/ChangeLog:
PR libstdc++/120235
* doc/html/*: Regenerate.
* doc/xml/manual/evolution.xml: Document deprecation.
* include/std/complex: Replace references to TR1 subclauses with
corresponding C++11 subclauses.
(fabs): Add deprecated attribute.
* testsuite/26_numerics/complex/fabs_neg.cc: New test.
Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>