mugdha@ubuntu:~/bin/HTK3.4$ make all
(cd HTKLib && make HTKLib.a) \
      || case "" in *k*) fail=yes;; *) exit 1;; esac;
make[1]: Entering directory `/home/mugdha/bin/HTK3.4/HTKLib'
gcc  -ansi -D_SVID_SOURCE -DOSS_AUDIO -D'ARCH="i686"' -Wall -Wno-switch -g -O2 -I. -DPHNALG   -c -o HGraf.o HGraf.c
HGraf.c:73:77: fatal error: X11/Xlib.h: No such file or directory
compilation terminated.
make[1]: *** [HGraf.o] Error 1
make[1]: Leaving directory `/home/mugdha/bin/HTK3.4/HTKLib'
make: *** [HTKLib/HTKLib.a] Error 1