I ran across this as I was building git on my aix server and this will hopefully help anyone else who finds this and wants to know the exact fileset the delivers the libxlsmp.a archive library.
The fileset that you will need to install off of the base media is:
You can run the following commands on a system that has the fileset installed or after you install it.
test123:/> lslpp -w /usr/lib/libxlsmp.a <- Since it didn't error out it must be a symlink and the -w option will need to be ran against the path that the link points to.
test123:/> ls -l /usr/lib/libxlsmp.a
lrwxrwxrwx 1 root system 31 Jan 19 17:49 /usr/lib/libxlsmp.a -> /usr/lpp/xlsmp/aix53/libxlsmp.a
test123:/> lslpp -w /usr/lpp/xlsmp/aix53/libxlsmp.a
File Fileset Type
/usr/lpp/xlsmp/aix53/libxlsmp.a xlsmp.aix53.rte File
So the archive library is included in the above fileset xlsmp.aix53.rte.
test123:/> lslpp -f xlsmp.aix53.rte
The -f flag to the lslpp command list all of the files that the fileset installs.
Hope this helps someone in the future if they want to get the fileset installed that will get rid of the error.