[Bug]: error: call of overloaded 'ldexp(long int, int)' is ambiguous

### Describe the issue

The compilation of abseil-cpp 20240116.3 fails on OpenIndiana with this error:

```
In file included from /usr/include/gtest/gtest.h:71,
from /data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/strings/charconv_test.cc:25:
/data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/strings/charconv_test.cc: In member function 'virtual void {anonymous}::FromChars_NearRoundingCasesExplicit_Test::TestBody()':
/data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/strings/charconv_test.cc:183:38: error: call of overloaded 'ldexp(long int, int)' is ambiguous
183 | EXPECT_EQ(ToDouble("5.e125"), ldexp(6653062250012735, 365));
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/math.h:35,
from /usr/gcc/14/include/c++/14.2.0/bits/std_abs.h:40,
from /usr/gcc/14/include/c++/14.2.0/cstdlib:81,
from /usr/gcc/14/include/c++/14.2.0/ext/string_conversions.h:43,
from /usr/gcc/14/include/c++/14.2.0/bits/basic_string.h:4154,
from /usr/gcc/14/include/c++/14.2.0/string:54,
from /usr/gcc/14/include/c++/14.2.0/stdexcept:39,
from /usr/gcc/14/include/c++/14.2.0/system_error:43,
from /data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/strings/charconv.h:18,
from /data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/strings/charconv_test.cc:15:
/usr/include/iso/math_iso.h:211:28: note: candidate: 'long double std::ldexp(long double, int)'
211 | inline long double ldexp(long double __X, int __Y) {
| ^~~~~
/usr/include/iso/math_iso.h:171:22: note: candidate: 'float std::ldexp(float, int)'
171 | inline float ldexp(float __X, int __Y) { return __ldexpf(__X, __Y); }
| ^~~~~
/usr/include/iso/math_iso.h:71:15: note: candidate: 'double std::ldexp(double, int)'
71 | extern double ldexp(double, int);
| ^~~~~
/data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/strings/charconv_test.cc:184:39: error: call of overloaded 'ldexp(long int, int)' is ambiguous
184 | EXPECT_EQ(ToDouble("69.e267"), ldexp(4705683757438170, 841));
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/iso/math_iso.h:211:28: note: candidate: 'long double std::ldexp(long double, int)'
211 | inline long double ldexp(long double __X, int __Y) {
| ^~~~~
/usr/include/iso/math_iso.h:171:22: note: candidate: 'float std::ldexp(float, int)'
171 | inline float ldexp(float __X, int __Y) { return __ldexpf(__X, __Y); }
| ^~~~~
/usr/include/iso/math_iso.h:71:15: note: candidate: 'double std::ldexp(double, int)'
71 | extern double ldexp(double, int);
| ^~~~~
```

### Steps to reproduce the problem

Compile abseil-cpp 20240116.3 with `-DABSL_BUILD_TESTING=ON` and `-DABSL_USE_EXTERNAL_GOOGLETEST=ON` on OpenIndiana.

### What version of Abseil are you using?

20240116.3

### What operating system and version are you using?

OpenIndiana (illumos distro)

### What compiler and version are you using?

```
$ gcc --version
gcc (OpenIndiana 14.2.0-oi-1) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$
```

### What build system are you using?

cmake version 3.31.5

### Additional context

_No response_