cross-GDC for tiny embedded Linux

[Dmitry Ponyatov]

Here the next problem of building `gcc-12.3.0` with 
`uClibc-ng-1.0.44` (i386 target):
```
libtool: compile:  
/home/ponyatov/player/tmp/gcc-12.3.0-1/./gcc/gdc 
-B/home/ponyatov/player/tmp/gcc-12.3.0-1/./gcc/ 
-B/home/ponyatov/player/host/i686-linux-uclibc/bin/ 
-B/home/ponyatov/player/host/i686-linux-uclibc/lib/ -isystem 
/home/ponyatov/player/host/i686-linux-uclibc/include -isystem 
/home/ponyatov/player/host/i686-linux-uclibc/sys-include -Wall 
-frelease -ffunction-sections -fdata-sections -O2 -g 
-fpreview=dip1000 -fpreview=fieldwise -fpreview=dtorfields 
-nostdinc -I 
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime -I . 
-c 
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/exception.d -o core/exception.o
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1227:40: error: undefined identifier '__SIZEOF_PTHREAD_MUTEX_T'
  1227 |         byte[__SIZEOF_PTHREAD_MUTEX_T] __size;
       |                                        ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1175:39: error: undefined identifier '__SIZEOF_PTHREAD_ATTR_T'
  1175 |         byte[__SIZEOF_PTHREAD_ATTR_T] __size;
       |                                       ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1192:39: error: undefined identifier '__SIZEOF_PTHREAD_COND_T'
  1192 |         byte[__SIZEOF_PTHREAD_COND_T] __size;
       |                                       ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1198:43: error: undefined identifier '__SIZEOF_PTHREAD_CONDATTR_T'
  1198 |         byte[__SIZEOF_PTHREAD_CONDATTR_T] __size;
       |                                           ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1233:44: error: undefined identifier '__SIZEOF_PTHREAD_MUTEXATTR_T'
  1233 |         byte[__SIZEOF_PTHREAD_MUTEXATTR_T] __size;
       |                                            ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1265:41: error: undefined identifier '__SIZEOF_PTHREAD_RWLOCK_T'
  1265 |         byte[__SIZEOF_PTHREAD_RWLOCK_T] __size;
       |                                         ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1271:45: error: undefined identifier '__SIZEOF_PTHREAD_RWLOCKATTR_T'
  1271 |         byte[__SIZEOF_PTHREAD_RWLOCKATTR_T] __size;
       |                                             ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1375:42: error: undefined identifier '__SIZEOF_PTHREAD_BARRIER_T'
  1375 |         byte[__SIZEOF_PTHREAD_BARRIER_T] __size;
       |                                          ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/sys/posix/sys/types.d:1381:46: error: undefined identifier '__SIZEOF_PTHREAD_BARRIERATTR_T'
  1381 |         byte[__SIZEOF_PTHREAD_BARRIERATTR_T] __size;
       |                                              ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/internal/array/capacity.d:64:37: error: template instance 'core.internal.array.utils._d_HookTraceImpl!(char[], _d_arraysetlengthT, "Cannot resize arrays if compiling without support for runtime type information!")' error instantiating
    64 |     alias _d_arraysetlengthTTrace = 
_d_HookTraceImpl!(Tarr, _d_arraysetlengthT, errorMessage);
       |                                     ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/demangle.d:226:17: note: instantiated from here: '_d_arraysetlengthTImpl!(char[], char)'
   226 |                 dst.length = minBufSize;
       |                 ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/demangle.d:2111:14: note: instantiated from here: 'Demangle!(NoHooks)'
  2111 |     auto d = Demangle!()(buf, dst);
       |              ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/demangle.d:2087:16: error: template instance 'core.demangle.Demangle!(PrependHooks).Demangle.doDemangle!(parseMangledName)' error instantiating
  2087 |         return doDemangle!parseMangledName();
       |                ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/demangle.d:2172:26: note: instantiated from here: 'Demangle!(PrependHooks)'
  2172 |         alias Remangle = Demangle!(PrependHooks);
       |                          ^
/home/ponyatov/player/ref/gcc-12.3.0/libphobos/libdruntime/core/demangle.d:2156:16: error: template instance 'object.RTInfo!(Replacement)' error instantiating
  2156 |         static struct Replacement
       |                ^
make[4]: *** [Makefile:2477: core/demangle.lo] Ошибка 1
make[4]: *** Ожидание завершения заданий…
make[4]: выход из каталога 
«/home/ponyatov/player/tmp/gcc-12.3.0-1/i686-linux-uclibc/libphobos/libdruntime»
```