statically compiled mysql

[Konstantin Svist]

>From http://dev.mysql.com/doc/refman/6.0/en/too-many-connections.html:
"The maximum number of connections MySQL can support depends on the
quality of the thread library on a given platform. Linux or Solaris
should be able to support 500-1000 simultaneous connections, depending
on how much RAM you have and what your clients are doing. Static Linux
binaries provided by Sun Microsystems, Inc. can support up to 4000
connections."

Sun claims their mysql binaries accept 4-8 times more connections
because of some threading library they use.
Has anyone tested this?
If true, [why] is linux threading system lagging behind so much?
What is this magical library?