[Bug libstdc++/54451] c++11/random.cc build failure when _GLIBCXX_USE_C99_STDINT_TR1 is not defined in config.h

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54451

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-09-09 17:19:44 UTC ---
(In reply to comment #4)
> Maybe it would be nice to use #error in header file to inform the user that
> this feature is not supported for target system (nicer than to get linker error
> later)

You won't get a linker error, if the macro is not defined then the types in
<random> are not declared, so code using them won't compile.

Using #error would prevent #include <random> which I don't think is a good
idea. There's no harm including the header as long as you don't try to use
types which require a working <stdint.h>

The fix is to simply make random.cc check the macro. This is what we already do
in future.cc and thread.cc and mutex.cc and other files too.