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

Solaris specific patch, will not send upstream

diff --git a/toolkit/components/startup/nsUserInfoUnix.cpp b/toolkit/components/startup/nsUserInfoUnix.cpp

--- a/toolkit/components/startup/nsUserInfoUnix.cpp

+++ b/toolkit/components/startup/nsUserInfoUnix.cpp

@@ -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;

     }