The strace use in the tests didn't work for me, so I altered it to actually
write some data and flush it repeatedly, and then timed that with and without
the LD_PRELOAD to prove that it is actually working:

$ time LD_PRELOAD=./libeatmydata.so ./fsynctest 

real    0m0.022s
user    0m0.009s
sys     0m0.014s
$ time ./fsynctest 

real    0m1.687s
user    0m0.016s
sys     0m0.382s

Here's the versions of OS, GCC, and ld I tested with:

$ uname -a
SunOS login 5.10 Generic_142900-01 sun4v sparc SUNW,SPARC-Enterprise-T5220
$ gcc --version
gcc (GCC) 3.4.3 (csl-sol210-3_4-branch+sol_rpath)
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ ld -V 
ld: Software Generation Utilities - Solaris Link Editors: 5.10-1.497