--- zio.c
+++ zio.c
@@ -62,7 +62,7 @@ static ssize_t   bzwrite(void *cookie, c
     return (ssize_t)BZ2_bzwrite((BZFILE*)cookie, (void*)buf, count);
 }
 
-static zio_int_t bzseek(void *cookie __unused, zio_off_t *poffset __unused, int whence __unused)
+static zio_int_t bzseek(void *cookie unused, zio_off_t *poffset unused, int whence unused)
 {
     errno = ESPIPE;
     return -1;
@@ -327,7 +327,7 @@ static ssize_t   lzwwrite(void *cookie,
     return -1;
 }
 
-static zio_int_t lzwseek(void *cookie __unused, zio_off_t *poffset __unused, int whence __unused)
+static zio_int_t lzwseek(void *cookie unused, zio_off_t *poffset unused, int whence unused)
 {
     errno = ESPIPE;
     return -1;
--- zioP.h
+++ zioP.h
@@ -33,14 +33,14 @@
 #include <stdlib.h>
 #include <errno.h>
 
-#ifndef  __unused
-# define __unused		__attribute__((__unused__))
+#ifndef  unused
+# define unused		__attribute__((__unused__))
 #endif
-#ifndef  __nonnull
-# define __nonnull(parm)	__attribute__((__nonnull__ parm))
+#ifndef  nonnull
+# define nonnull(parm)	__attribute__((__nonnull__ parm))
 #endif
-#ifndef  __wur
-# define __wur			__attribute__((__warn_unused_result__))
+#ifndef  wur
+# define wur		__attribute__((__warn_unused_result__))
 #endif
 
 #if !defined(HAVE_FOPENCOOKIE) && !defined(HAVE_FUNOPEN)
@@ -161,9 +161,9 @@ __extension__ typedef struct
 } cookie_io_functions_t;
 static __inline__ FILE *fopencookie(void *__restrict,
 				    const char *__restrict,
-				    cookie_io_functions_t) __nonnull((1,2)) __wur;
+				    cookie_io_functions_t) nonnull((1,2)) wur;
 static __inline__ FILE *fopencookie(void *__restrict cookie,
-				    const char *__restrict mode __unused,
+				    const char *__restrict mode unused,
 				    cookie_io_functions_t io_funcs)
 {
     return funopen(cookie, io_funcs.read, io_funcs.write, io_funcs.seek, io_funcs.close);