[Bug libstdc++/59087] Issues including complex.h in C++11/1y mode because of C's complex.h

[3dw4rd at verizon dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59087

Ed Smith-Rowland <3dw4rd at verizon dot net> changed:

           What    |Removed                     |Added
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                 CC|                            |3dw4rd at verizon dot net

--- Comment #5 from Ed Smith-Rowland <3dw4rd at verizon dot net> ---
complex.h
---------
...
#define _Complex_I    (__extension__ 1.0iF)
...

So yes, this looks to C++11 etc. like a user-defined literal suffix.  Except
that the user-defined literal suffix interpretation is supposed to let standard
suffixes and implementation-defined suffixes get first crack.  Maybe there's a
hole in that logic?

Now figure out what __extension__ does and see if it can be used somehow to
intercept the usual suffix processing?  That just suppresses -pedantic.

Just thinking aloud.  I'm on it.