GTK2 does not use "gtk-config". It is obsolete. GTK2 now uses "pkgconfig". Which seems to be missing. I looked right through that beofre. :P

make[1]: Entering directory `/home/mugs/Desktop/gk/gkrellm-2.1.4/src'
cc -Wall -O2 -I.. `pkg-config --cflags gtk+-2.0 gthread-2.0` -DENABLE_NLS -DLOCALEDIR=\"/usr/share/locale\" -c -o main.o main.c
/bin/sh: pkg-config: command not found