[lazarus] Can't run Lazarus in Slackware

[Zdravko]

Hello,

Could you tell me what are requirements to install successfully Lazarus.
I am using Linux Slackeware 4.0. 
I have just install the latest gtk-1.2.6 libraries.

I had a problem compiling it. Several things was not declared in
gtkcallback.inc file.
I commented them and manage to compile.
The created lazarus complains and fails to start.
Messages are mostly related to gtkwidget.c and related files.

Thank you in advance.

Best regards
Zdravko