libstdc++ should define `std::to_string(double)` after `#include <string>`.

The version of `libstdc++` for 64-bits does so.

The version of `libstdc++` for 32-bits does not.  This is a problem.



Reproducible: Always

Steps to Reproduce:
1. dnf makecache && dnf install -y gcc-c++ glibc-devel libstdc++-devel glibc-devel.i686 libstdc++-devel.i686
2. printf "#include <string>\n#include <iostream>\n\nint main() { std::cout << std::to_string(1.0) << std::endl; }\n" >test.cc
3. g++ -m32 test.cc
Actual Results:  
test.cc: In function ‘int main()’:
test.cc:4:41: error: call of overloaded ‘to_string(double)’ is ambiguous
    4 | int main() { std::cout << std::to_string(1.0) << std::endl; }
      |                           ~~~~~~~~~~~~~~^~~~~
In file included from /usr/include/c++/13/string:54,
                 from test.cc:1:
/usr/include/c++/13/bits/basic_string.h:4150:3: note: candidate: ‘std::string std::__cxx11::to_string(int)’
 4150 |   to_string(int __val)
      |   ^~~~~~~~~

Expected Results:  
A successful compilation without errors.


It seems `std::to_string()` overloads for `float`, `double` and `long double` are protected by a `#if _GLIBCXX_USE_C99_STDIO`:

https://github.com/gcc-mirror/gcc/blob/c891d8dc23e1a46ad9f3e757d09e57b500d40044/libstdc%2B%2B-v3/include/bits/basic_string.h#L4224-L4235

That macro is defined in terms of `_GLIBCXX11_USE_C99_STDIO`:

echo '#include <string>' | g++ -m32 -x c++ -dM -E - | grep _GLIBCXX_USE_C99_STDIO
#define _GLIBCXX_USE_C99_STDIO _GLIBCXX11_USE_C99_STDIO

That macro appears in the 64-bit version of `bits/c++config.h`:

grep  _GLIBCXX11_USE_C99_STDIO /usr/include/c++/13/x86_64-redhat-linux/bits/c++config.h
# define _GLIBCXX_USE_C99_STDIO _GLIBCXX11_USE_C99_STDIO
/* #undef _GLIBCXX11_USE_C99_STDIO */
# define _GLIBCXX_USE_C99_STDIO _GLIBCXX11_USE_C99_STDIO
#define _GLIBCXX11_USE_C99_STDIO 1

But does not appear in the 32-bit version:

grep  _GLIBCXX11_USE_C99_STDIO /usr/include/c++/13/x86_64-redhat-linux/32/bits/c++config.h
# define _GLIBCXX_USE_C99_STDIO _GLIBCXX11_USE_C99_STDIO
/* #undef _GLIBCXX11_USE_C99_STDIO */


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FWIW, this compiles successfully with Fedora:38.