In bind 9.9, export libraries are installed with INSTALL_DATA. In Fedora
we use libtool with dynamically linked export libraries for DHCP
packages. Package build is broken after upgrade to 9.9.10.

It does expand variables to this on Fedora 25:
INSTALL_DATA =          ${INSTALL} -m 644
INSTALL_LIBRARY =       ${INSTALL_PROGRAM}

Installed export dynamic libraries are then installed without execute
bit. I think lib/export was forgotten when backporting commit
38398c590ab7aeb5c3d3749c1a8d672e6f2f138c into v9_9 branch.