libstdc++/6641: -D__USE_MALLOC doesn't link

[ljrittle@gcc.gnu.org]

Synopsis: -D__USE_MALLOC doesn't link

Responsible-Changed-From-To: unassigned->ljrittle
Responsible-Changed-By: ljrittle
Responsible-Changed-When: Mon May 13 13:20:30 2002
Responsible-Changed-Why:
    My pet issue.
State-Changed-From-To: open->closed
State-Changed-By: ljrittle
State-Changed-When: Mon May 13 13:20:30 2002
State-Changed-Why:
    You are correct in that this is a change from 2.95 and
    perhaps 3.0 (the only correct use of __USE_MALLOC was
    surely documented by the 3.0 release but it is possible
    that it still "worked").
    
    The libstdc++-v3 documentation now explicitly says that
    you must rebuild the entire library to define library
    implementation macros such as __USE_MALLOC.
    
    The use of macros in the library implementation name space,
    such as __USE_MALLOC, which may change internal
    implementation can violate the one-definition rule of C++.
    
    A patch that correctly handles all one-definition issues
    with such a macro might be accepted.  However, I will be
    holding my nose.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6641