--- src/gmalloc.c
+++ src/gmalloc.c	2017-03-20 15:02:35.000000000 +0000
@@ -1199,18 +1199,6 @@ along with the GNU C Library.  If not, s
 #include <malloc.h>
 #endif
 
-/* #ifndef	__GNU_LIBRARY__ */
-#define	__sbrk	sbrk
-/* #endif */
-
-#ifdef __GNU_LIBRARY__
-/* It is best not to declare this and cast its result on foreign operating
-   systems with potentially hostile include files.  */
-#if !(defined(linux) && defined(sparc))
-extern __ptr_t __sbrk __P ((int increment));
-#endif
-#endif
-
 #ifndef NULL
 #define NULL 0
 #endif