runtime: Fix plan9 aes hash initialization.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7593045

src/pkg/runtime/env_plan9.c

@@ -20,7 +20,7 @@ runtime·getenv(int8 *s)
 	runtime·memmove((void*)file, (void*)"/env/", 5);
 	runtime·memmove((void*)(file+5), (void*)s, len);
 
-	fd = runtime·open(file, OREAD);
+	fd = runtime·open((int8*)file, OREAD, 0);
 	if(fd < 0)
 		return nil;
 	n = runtime·seek(fd, 0, 2);

src/pkg/runtime/os_plan9.h

@@ -3,12 +3,9 @@
 // license that can be found in the LICENSE file.
 
 // Plan 9-specific system calls
-int32	runtime·open(uint8 *file, int32 mode);
 int32	runtime·pread(int32 fd, void *buf, int32 nbytes, int64 offset);
 int32	runtime·pwrite(int32 fd, void *buf, int32 nbytes, int64 offset);
-int32	runtime·read(int32 fd, void *buf, int32 nbytes);
 int64	runtime·seek(int32 fd, int64 offset, int32 whence);
-int32	runtime·close(int32 fd);
 void	runtime·exits(int8* msg);
 intptr	runtime·brk_(void*);
 int32	runtime·sleep(int32 ms);

src/pkg/runtime/thread_plan9.c

@@ -48,7 +48,7 @@ getproccount(void)
 	int32 fd, i, n, ncpu;
 	byte buf[2048];
 
-	fd = runtime·open((byte*)"/dev/sysstat", OREAD);
+	fd = runtime·open("/dev/sysstat", OREAD, 0);
 	if(fd < 0)
 		return 1;
 	ncpu = 0;
@@ -72,7 +72,7 @@ getpid(void)
 	int32 fd;
 
 	runtime·memclr(b, sizeof(b));
-	fd = runtime·open((byte*)"#c/pid", 0);
+	fd = runtime·open("#c/pid", 0, 0);
 	if(fd >= 0) {
 		runtime·read(fd, b, sizeof(b));
 		runtime·close(fd);
@@ -91,6 +91,13 @@ runtime·osinit(void)
 	runtime·notify(runtime·sigtramp);
 }
 
+void
+runtime·get_random_data(byte **rnd, int32 *rnd_len)
+{
+	*rnd = nil;
+	*rnd_len = 0;
+}
+
 void
 runtime·goenvs(void)
 {
@@ -195,7 +202,7 @@ runtime·postnote(int32 pid, int8* msg)
 	p--;
 	runtime·memmove((void*)p, (void*)"/note", 5);
 
-	fd = runtime·open(buf, OWRITE);
+	fd = runtime·open((int8*)buf, OWRITE, 0);
 	if(fd < 0)
 		return -1;