I tried this question on fedora-list yesterday, and got a number of messages from other users with the same problem, but no resolution. Perhaps this list is a better place to ask? A silly question: How does one build or rebuild src rpms under x86_64? On a freshly installed FC3 (full install) nearly everything fails to build as configure looks at the wrong X11 libraries. As an example, rebuilding mozilla: $ rpmbuild --rebuild mozilla-1.7.5-3.src.rpm ...lines deleted... checking GLIB_LIBS... -lglib-2.0 configure: error: Could not find the following X libraries: -lX11 -lXext -lXt error: Bad exit status from /var/tmp/rpm-tmp.13288 (%build) Modifying the spec-file to add a line like this cures the problem: --x-libraries=/usr/X11R6/lib64 But this is probably too crude - what is the proper incantation to make rpmbuild understand where the X11 libraries are placed on x86_64? -psi