Bug in autoconf script

[jeroen]

Statically linking on OSX fails because homebrew builds --with-szip but you are not passing the proper -lsz flag to PKG_LIBS.

We get the correct flags from ${H5CPP} -show which you do call in the configure script. However you are overriding the libs with hardcoded -lhdf5_cpp -lhdf5 -lz -lm which does not include -lsz. Therefore linking fails for hdf5 builds that are configured --with-static.

The fix is simply to just use ${H5CPP} -show in your PKG_LIBS.