Remove internal functions from headers

Those functions were exposed by stdc to be used by posixc, but now they
are used internally in crt and not exposed by crt.

compiler/crt/__stdc_intbase.h

@@ -50,5 +50,7 @@ struct StdCIntBase
 };
 
 struct StdCBase *__aros_getbase_StdCBase(void);
+int __stdc_ioerr2errno(int ioerr);
+char *__stdc_strerror(int n);
 
 #endif

compiler/stdc/include/aros/stdc/errno.h

@@ -87,11 +87,6 @@ int *___geterrnoptr(void);
 #define errno (*___geterrnoptr())
 #endif
 
-/* AROS specific functions to translate DOS error numbers to errno.
- */
-int ioerr2errno(int ioerr);
-int __stdc_ioerr2errno(int ioerr); 
-
 __END_DECLS
 
 #endif /* _STDC_ERRNO_H_ */

compiler/stdc/include/aros/stdc/string.h

@@ -48,8 +48,6 @@ void *memset (void * dest, int c, size_t n);
 char *strerror (int n);
 size_t strlen (const char * str);
 
-/* AROS specific function */
-char *__stdc_strerror(int n); /* This will be aliased to strerror() */
 
 __END_DECLS