system module?

[Eric Blake]

Andreas Buening reported that OS/2 violates the CX shading in POSIX 2001 in 
that the return value of system() is not parseable with WEXITSTATUS:

http://www.nabble.com/Re%3A-sysval-and-doc-fixes--was%3A-GNU-M4-1.4.4b-released-
%28beta-release%29--t1815393.html#a4961536

In short, on OS/2, waitpid() and pclose() use (status>>8)&0xff, but system() 
uses status&0xff, to represent the low 8 bits returned from main() in the child 
process.

Is it worth adding a system module to gnulib that detects implementations with 
this bug, and provides rpl_system to work around it?

-- 
Eric Blake