[ns] problem with compiling ns-2.1b6

["SungJin Lee" <bluezy@dreamwiz.com>]

When I type ./configure in ns-2.1b6 directory
It doesn't configure 'tk.h' correctly
What should i do for this error .. ?   :(


-------------------------------------------------------
>./configure

loading cache ./config.cache
No .configure file found in current directory
Continuing with default options...
checking host system type... i686-pc-linux-gnu
checking target system type... i686-pc-linux-gnu
checking build system type... i686-pc-linux-gnu
checking for gcc... gcc
checking whether the C compiler (gcc  ) works... yes
checking whether the C compiler (gcc  ) is a cross-compiler... no
checking whether we are using GNU C... yes
checking whether gcc accepts -g... yes
checking for c++... c++
checking whether the C++ compiler (c++  ) works... yes
checking whether the C++ compiler (c++  ) is a cross-compiler... no
checking whether we are using GNU C++... yes
checking whether c++ accepts -g... yes
checking how to run the C preprocessor... gcc -E
checking for ANSI C header files... yes
checking for string.h... yes
checking for main in -lXbsd... no
checking for socket in -lsocket... no
checking for gethostbyname in -lnsl... yes
checking for dcgettext in -lintl... no
checking for getnodebyname in -ldnet_stub... no
checking that c++ can handle -O2... yes
checking for tcl.h... -I../tcl8.0.4/generic
checking for libtcl8.0... -L../tcl8.0.4/unix -ltcl8.0
checking for init.tcl... /usr/local/bin/ns-allinone-2.1b6/ns-2.1b6/../tcl8.0.4/library
d is 
checking for tclsh8.0.4... no
checking for tclsh8.0... no
checking for tclsh... /usr/bin/tclsh
checking for tk.h...  configure: error: NONE is not a directory

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