It puzzled me as well.
The lsphp5 binary are linked with " -R /opt/xml2/lib", so it suppose to look for libxml2.so.2 under /opt/xml2/lib directory. But somehow it find /usr/lib64/libxml2.so.2 first.
Something wrong with the linker?
Can you try "strace ./lsphp5 -i" , it should show how libxml2.so was located.
compare it to "strace /usr/local/bin/php -i".