During a testbuild of vnc-4.0-8.1 in mock, the rebuild process stops
with the following error in the %configure phase:

gcc -c -O2 -g -pipe -m64  -ansi -pedantic -Wall -Wpointer-arith -Wundef  
-I/usr/include/freetype2 -I/usr/include/freetype2/co
nfig -I../../extras/fontconfig/src      -I../../extras/fontconfig
-I../../exports/include/X11  -I../.. -I../../exports/include
   -Dlinux -D__amd64__ -D_POSIX_C_SOURCE=199309L                               
-D_POSIX_SOURCE -D_XOPEN_SOURCE
                        -D_BSD_SOURCE -D_SVID_SOURCE                           
 -D_GNU_SOURCE                            -DFU
NCPROTO=15 -DNARROWPROTO -DXTHREADS  -D_REENTRANT -DXUSE_MTSAFE_API   
-DFC_DEFAULT_FONTS='""' -DHAVE_EXPAT -DXFREE86_FT2
        -DFONTCONFIG_PATH='"/etc/fonts"'     -fPIC fcxml.c
fcxml.c:35:19: expat.h: No such file or directory
[...]
fcxml.c:485: error: `va_start' used in function with fixed args
make[4]: *** [fcxml.o] Error 1
make[4]: Leaving directory `/builddir/build/BUILD/vnc-4.0-unixsrc/xc/lib/fontconfig'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/builddir/build/BUILD/vnc-4.0-unixsrc/xc/lib'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/builddir/build/BUILD/vnc-4.0-unixsrc/xc'
make[1]: *** [World] Error 2
make[1]: Leaving directory `/builddir/build/BUILD/vnc-4.0-unixsrc/xc'
make: *** [World] Error 2
error: Bad exit status from /var/tmp/rpm-tmp.65714 (%build)


Adding expat-devel to the BuildRequires list should fix this problem.