This is caused by a bug in the new pkg-config, but I thought you might want to
know about it since it affects epiphany, and can be worked around simply.

The relevant pkg-config bug report is here:
  https://bugs.freedesktop.org/show_bug.cgi?id=3006

It is caused by a repeated name in the list passed to PKG_CHECK_MODULES().  Here
is a patch that works around the bug:

Index: configure.ac
===================================================================
RCS file: /cvs/gnome/epiphany/configure.ac,v
retrieving revision 1.68.2.11
diff -u -p -r1.68.2.11 configure.ac
--- configure.ac        11 Apr 2005 22:30:55 -0000      1.68.2.11
+++ configure.ac        13 Apr 2005 08:40:14 -0000
@@ -92,7 +92,6 @@ PKG_CHECK_MODULES([EPIPHANY_DEPENDENCY],
                  libglade-2.0 >= $LIBGLADE_REQUIRED \
                  bonobo-activation-2.0 \
                  ORBit-2.0 \
-                 libglade-2.0 >= $LIBGLADE_REQUIRED \
                  gnome-vfs-2.0 >= $LIBGNOMEVFS_REQUIRED \
                  gnome-vfs-module-2.0 \
                  gconf-2.0 \

The pkg-config bug will affect people building the epiphany tarball, if they
have pkg-config-0.17.1 installed (possibly also 0.16 or 0.17 too -- I haven't
checked them).