Intsall error (emboss)

[Kerti Balazs Gabor]

Hi All!

I would like to install the program Emboss 
(http://emboss.sourceforge.net/support/index.html) from source.
The scrip
configure --enable-64 # enable 64 bit support AMD64
ran well, but the
make
made error this, what I do not understand:

then mv -f ".deps/aaindexextract.Tpo" ".deps/aaindexextract.Po"; else rm 
-f ".deps/aaindexextract.Tpo"; exit 1; fi
/bin/sh ../libtool --tag=CC --mode=link gcc  -O2   -o aaindexextract 
aaindexextract.o ../nucleus/libnucleus.la ../ajax/libajaxg.la 
../ajax/libajax.la ../plplot/libplplot.la -lX11  -lm
mkdir .libs
gcc -O2 -o .libs/aaindexextract aaindexextract.o 
../nucleus/.libs/libnucleus.so ../ajax/.libs/libajaxg.so 
../ajax/.libs/libajax.so ../plplot/.libs/libplplot.so -lX11 -lm 
-Wl,--rpath -Wl,/usr/local/lib
/usr/bin/ld: cannot find -lX11
collect2: ld returned 1 exit status
make[2]: *** [aaindexextract] Error 1
make[2]: Leaving directory `/usr/src/EMBOSS-2.10.0/emboss'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/usr/src/EMBOSS-2.10.0/emboss'
make: *** [all-recursive] Error 1

How to solve this?

Balazs