#include <unixlib.h>
#else
/* For systems with larger pointers than ints, these must be declared. */
-PTR malloc (size_t);
-PTR realloc (PTR, size_t);
-PTR calloc (size_t, size_t);
-PTR sbrk (ptrdiff_t);
-#endif
+# if HAVE_STDLIB_H && HAVE_UNISTD_H && HAVE_DECL_MALLOC \
+ && HAVE_DECL_REALLOC && HAVE_DECL_CALLOC && HAVE_DECL_SBRK
+# include <stdlib.h>
+# include <unistd.h>
+# else
+# ifdef __cplusplus
+extern "C" {
+# endif /* __cplusplus */
+void *malloc (size_t);
+void *realloc (void *, size_t);
+void *calloc (size_t, size_t);
+void *sbrk (ptrdiff_t);
+# ifdef __cplusplus
+}
+# endif /* __cplusplus */
+# endif /* HAVE_STDLIB_H ... */
+#endif /* VMS */
/* The program name if set. */
static const char *name = "";