[Issue 21659] New: [OSX] core.stdc.config.__c_ulonglong is forward referenced while looking for sizeof

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21659

          Issue ID: 21659
           Summary: [OSX] core.stdc.config.__c_ulonglong is forward
                    referenced while looking for sizeof
           Product: D
           Version: D2
          Hardware: All
                OS: Mac OS X
            Status: NEW
          Keywords: industry, rejects-valid
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: pro.mathias.lang at gmail.com

Compiling the following with the latest (v2.095.1) on OSX:
```
import core.stdc.inttypes;
import std.bitmanip;

void main ()
{
    uint64_t record;
    auto x = nativeToLittleEndian(record)[0 .. typeof(record).sizeof];
}
```

Will trigger the following error:
```
/usr/local/opt/dmd/include/dlang/dmd/core/stdc/config.d(121): Error: enum
core.stdc.config.__c_ulonglong is forward referenced when looking for sizeof
/usr/local/opt/dmd/include/dlang/dmd/std/bitmanip.d(2958): Error: template
instance std.bitmanip.EndianSwapper!(__c_ulonglong) error instantiating
/usr/local/opt/dmd/include/dlang/dmd/std/bitmanip.d(3092):        instantiated
from here: nativeToEndianImpl!(false, __c_ulonglong)
reg.d(7):        instantiated from here: nativeToLittleEndian!(__c_ulonglong)
/usr/local/opt/dmd/include/dlang/dmd/core/stdc/config.d(121): Error: enum
core.stdc.config.__c_ulonglong is forward referenced when looking for sizeof
/usr/local/opt/dmd/include/dlang/dmd/std/bitmanip.d(2966): Error: template
instance std.bitmanip.ctfeBytes!(__c_ulonglong) error instantiating
/usr/local/opt/dmd/include/dlang/dmd/std/bitmanip.d(3092):        instantiated
from here: nativeToEndianImpl!(false, __c_ulonglong)
reg.d(7):        instantiated from here: nativeToLittleEndian!(__c_ulonglong)
```

However, it will work fine on Linux. This error appeared also on Linux in an
release (v2.078 to v2.080) but was fixed.

--