Stub out SYS_sendmmsg syscall

Author: jgravelle-google

src/library_syscall.js

@@ -1260,6 +1260,12 @@ var SyscallsLibrary = {
     }
     return 0;
   },
+  __syscall345: function(which, varargs) { // sendmmsg
+#if SYSCALL_DEBUG
+    Module.printErr('warning: ignoring SYS_sendmmsg');
+#endif
+    return 0;
+  },
 };
 
 if (SYSCALL_DEBUG) {

system/lib/libc/musl/arch/emscripten/syscall_arch.h

@@ -142,6 +142,7 @@ long __syscall331(int which, ...);
 long __syscall333(int which, ...);
 long __syscall334(int which, ...);
 long __syscall340(int which, ...);
+long __syscall345(int which, ...);
 
 #undef SYS_futimesat
 

system/lib/libc/musl/src/network/sendmmsg.c

@@ -25,10 +25,6 @@ int sendmmsg(int fd, struct mmsghdr *msgvec, unsigned int vlen, unsigned int fla
 error:
 	return i ? i : -1;
 #else
-#ifndef __EMSCRIPTEN__
 	return syscall_cp(SYS_sendmmsg, fd, msgvec, vlen, flags);
-#else
-	return -1;
-#endif
 #endif
 }