i haven’t used makefiles very much myself, but i think you need a new line after “all:”
and then a tab. also, you should try to generalize your paths, for example TOP=. and INCLUDE= $(TOP)/include, SRC=$(TOP)/src etc. this makes you more flexible. anyway, i don’t understand your error message. probably an error in glext.h?
The makefile could perhaps been little easier but the only error I could see was
CC is set to cc this is the C compiler. CXX is indicating C++ and if you want to specify a C++ compiler should it be something like c++ and not cc.
Anyway, you do not use CXX so your makefile builds the program just as good as any other makefile. The problem is in your code, probably do you forget to include some header.