As Enda O'Connor wrote in a Comment to the mentioned Blogpost, you have to install additional Packages. At least you need to install SUNWgawk. I recommend to check, if you have all needed Headers installed (like SUNWxorg-headers).
To make sure the GNU-Version of awk will be used while compiling, add it to your PATH-Variable:
$: export PATH=/usr/gnu/bin:$PATH
On my Machine (IBM z61m Noteboook) I had to disable MMX to compile:
$: ./configure --prefix=/opt/mplayer --enable-gui
Unfortunatly I could compile and install MPlayer whitout Errors, but if I start it I get the following Message:
Obviously something went totally wrong :-( I will try to compile (and configure) MPlayer again, and provide an Update if its running.
UPDATE: See next Blogpost. Disabling of MMX was not necessary!