Description of problem:
feh doesn't build under current fc5/devel mock due to missing BuildRequires

End of build.log from mock:

gcc -DHAVE_CONFIG_H -I. -I. -I. -I/usr/X11R6/include                     
-I/usr/include -I/usr/include                     -I. -I../src                 
   -I/usr/local/include/libpng      -DPREFIX=\""/usr"\"                     
-I/usr/include/giblib    -I/usr/X11R6/include -O2 -g -pipe -Wall
-Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4
-m32 -march=i386 -mtune=pentium4 -fasynchronous-unwind-tables
-I/usr/X11R6/include -c options.c
In file included from main.c:32:
support.h:30:85: error: X11/Intrinsic.h: No such file or directory
make[3]: *** [main.o] Error 1
make[3]: *** Waiting for unfinished jobs....
options.c: In function 'feh_parse_option_array':
options.c:481: warning: pointer targets in passing argument 4 of
'XParseGeometry' differ in signedness
options.c:481: warning: pointer targets in passing argument 5 of
'XParseGeometry' differ in signedness
options.c:416: warning: unused variable 'geomret'
options.c:415: warning: unused variable 'i'
make[3]: Leaving directory `/builddir/build/BUILD/feh-1.3.4/src'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/builddir/build/BUILD/feh-1.3.4/src'
make[1]: *** [all-recursive-am] Error 2
make[1]: Leaving directory `/builddir/build/BUILD/feh-1.3.4/src'
make: *** [all-recursive] Error 1
error: Bad exit status from /var/tmp/rpm-tmp.26065 (%build)


RPM build errors:
    Bad exit status from /var/tmp/rpm-tmp.26065 (%build)

Looks like missing a BuildRequires for libXt-devel in modular xorg.