gcc for Linux/x86 vs. Solaris/x86

[Alexandra (Sasha) Fedorova]

I was wondering anyone knows any details of the gcc port for Solaris/x86. 
I am wondering, if I have an executable compiled with gcc for Linux and an 
executable compiled with the same gcc (same version, same options) for 
Solaris, how similar would those executables be? I understand that the 
code running in shared libraries and system calls will be different, but 
it seems that the rest (user-level) code should be the same, since it is 
generated by essentially the same compiler. What do you think?

-- Sasha