check the dynamic link problem.

when I used gnuplot, it gives some error. Use the following to check and find the reasons for the error.


> ldd `which gnuplot`
linux-gate.so.1 => (0xffffe000)
libreadline.so.5 => /lib/libreadline.so.5 (0xb7ee5000)
libncurses.so.5 => /lib/libncurses.so.5 (0xb7ea4000)
libz.so.1 => /usr/lib/libz.so.1 (0xb7e8f000)
libstdc++.so.5 => not found
libm.so.6 => /lib/tls/i686/cmov/libm.so.6 (0xb7e6a000)
libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb7e5f000)
libc.so.6 => /lib/tls/i686/cmov/libc.so.6 (0xb7d2e000)
libdl.so.2 => /lib/tls/i686/cmov/libdl.so.2 (0xb7d2a000)
/lib/ld-linux.so.2 (0xb7f31000)
It is clear that libstdc++.so.5 not found. So need to install it.