The uname() function on Solaris can return a non-negative value. 

--- comm-esr31/mozilla/toolkit/components/startup/nsUserInfoUnix.cpp.orig	2015-06-04 17:42:51.565111934 -0700
+++ comm-esr31/mozilla/toolkit/components/startup/nsUserInfoUnix.cpp	2015-06-04 17:42:51.567398410 -0700
@@ -106,7 +106,7 @@
     char *domainname = nullptr;
 
     // is this portable?  that is a POSIX compliant call, but I need to check
-    if (uname(&buf)) { 
+    if (uname(&buf) < 0) { 
         return rv;
     }