install xorg-server

[oxy]

hi

i downloaded xorg-server-1.12.1 and did './configure' inside and got:

    "checking for GL... no
     configure: error: Package requirements (glproto >= 1.4.14 gl >=
7.1.0) were not met:

     No package 'gl' found

     Consider adjusting the PKG_CONFIG_PATH environment variable if you
     installed software in a non-standard prefix."

Any idea?
thx...

Ubu 12.04 64bit