libmain: remove explicit std::cerr buffering

we don't use std::cerr often enough to want this, and since cerr flushes
after every operation anyway it never did anything useful to begin with.

Change-Id: Ia54be340826da5073e9a1786c463555f4f0e491c

lix/libmain/shared.cc

@@ -146,10 +146,6 @@ void initNix()
 
     registerCrashHandler();
 
-    /* Turn on buffering for cerr. */
-    static char buf[1024];
-    std::cerr.rdbuf()->pubsetbuf(buf, sizeof(buf));
-
     // libutil
     GlobalConfig::registerGlobalConfig(loggerSettings);
     GlobalConfig::registerGlobalConfig(featureSettings);