The isdn4k-utils-3.1-72.src.rpm package is missing a 
buildrequires: tcl-devel 
line as it does not successfully if this package is not available:

...
checking tcl.h usability... no
checking tcl.h presence... no
checking for tcl.h... no 
configure: WARNING: "**" 
configure: WARNING: "** Unable to find a installed tcl package!"
configure: WARNING: "**"
configure: error: "stop" 
make[1]: Entering directory `/usr/local/es/taroon/RedHat/BUILD/isdn4k-utils'

WARNING! Configure in vbox failed, disabling package

make[1]: Leaving directory `/usr/local/es/taroon/RedHat/BUILD/isdn4k-utils'

...

+ chmod 0755 /var/tmp/isdn4k-utils-root/usr/bin/vboxbeep 
/var/tmp/isdn4k-utils-root/usr/sbin/isdnctrl
chmod: failed to get attributes of 
`/var/tmp/isdn4k-utils-root/usr/bin/vboxbeep': No such file or directory
error: Bad exit status from /var/tmp/rpm-tmp.72320 (%install)