well gcc i a C compiler, and if you did not choose de include developpement tools during your install the configure messages are normal. You need to install gcc, there must be a package named gcc-something on your mandrake cd, try to install that.
TCL is a programming language, but it is interpreted, as opposed to C, C++, whatever other compiled languages. TCL is used by eggdrop as a way to add fonctions, make your own etc.
