pmix: OMPI configure error with external PMIx that installed to `lib64` path

[karasevb]

If there is the installed PMIx in lib64 path then an attempt to configure the OMPI with it looks follow:

$ ls /opt/pmix/lib64
/opt/pmix/lib64/libpmix.la
/opt/pmix/lib64/libpmix.so
/opt/pmix/lib64/libpmix.so.2
/opt/pmix/lib64/libpmix.so.2.0.3

$ ./configure –with-pmix=/opt/pmix
...
checking --with-external-pmix value... sanity check ok (/opt/pmix/include)
checking --with-external-libpmix value... not found
configure: WARNING: Directory /opt/pmix/lib not found
configure: error: Cannot continue