System calls: simple stubs

[mrsmkl]

The following system calls just need simple stubs. They could be handled using the generic system calls, but it will be more efficient to add stubs.
29. Pause:nothing to implement
34. Nice: nothing to implement
35. Sync: nothing to implement
42. Pipe: nothing to implement
51. Acct: nothing to implement, but what is it?
66. Setsid: nothing to implement
75. Setrlimit: nothing to implement
96. Getpriority: nothing to implement
97. Setpriority: nothing to implement
104. Setitimer: nothing to implement
114. Wait4: nothing to implement
118. Fsync: nothing to implement?
121. setdomainname: nothing to implement
125. Mprotect: nothing to implement
148. Fdatasync: Nothing
150. Mlock: nothing
151. Munlock: nothing
152. Mlockall: nothing
153. Munlockall: nothing
163. Mremap: nothing
199, 200, 201, 202: getuid32, getgid32, geteuid32, getgid32: nothing
203, 204, 213, 214. Setreuid32, setregid32, setuid32, getuid32: nothing
218. Mincore: nothing
219. Madvise: nothing
265. Clock_nanosleep: nothing
272. Fadvise64: nothing
299. Futimesat: nothing
303. Linkat: nothing
308. Pselect: nothing
331. Pipe2: nothing

[terminaldweller]

how do you want them stubbed?

[mrsmkl]

So that they work like in https://github.com/kripken/emscripten/blob/master/src/library_syscall.js
Mostly this means that they will just return some constant value.