Add mseal(2) wrapper.

Change-Id: I053b2d570cd5750285fc20e9e237e04d59778bf5
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 182de17..0899264 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -126,6 +126,7 @@
 int mlock2(const void* addr, size_t len, int flags)    all
 int         munlock(const void* addr, size_t len)   all
 int         mlockall(int flags)   all
+int mseal(void*, size_t, unsigned long) lp64
 int         munlockall()   all
 int         mincore(void*  start, size_t  length, unsigned char*  vec)   all
 int         __ioctl:ioctl(int, int, void*)  all