Hello Everyone!

Im installing spim on ubuntu which i got from SPIM MIPS Simulator.
Ive followed the steps but suddenly i got these following errors.

Code:
jars@jars-desktop:~/Desktop/spim/spim-8.0/xspim$ xmkmf
mv -f Makefile Makefile.bak
imake -DUseInstalled -I/usr/lib/X11/config
<stdin>:1:19: error: stdio.h: No such file or directory
<stdin>:2:19: error: ctype.h: No such file or directory
<stdin>: In function ‘main’:
<stdin>:18: error: ‘NULL’ undeclared (first use in this function)
<stdin>:18: error: (Each undeclared identifier is reported only once
<stdin>:18: error: for each function it appears in.)
<stdin>:45: warning: incompatible implicit declaration of built-in function ‘sscanf’
<stdin>:49: warning: incompatible implicit declaration of built-in function ‘printf’
Aborted
im stucked right there and i dont know what to do. can anyone help me?

Thanks in advance!
Have a nice day!