pqiv-2.8.2

This is the release of pqiv 2.8.2

This fixes an error in the build system. Old glib versions do not expose their
private dependency on x11 in their pkgconfig file, and therefore pqiv failed to
link to x11, resulting in a linker error. The new version instead uses the
"target" variable of gtk+ ("targets" in recent versions of gtk) to check
whether x11 is available.