CentOS 5 :: Unable To GCC Compile Any Stuff - Random Errors

I am new to CENTOS (5.2) and more importantly new to linux. Any time I try to gcc compile something, it always throws random errors. I yum installed development-tools which is what I have seen other threads suggest but that did not solve the issue. I still get the same errors. I cannot find a common error among the many things I have attempted to compile.

Here is my most recent file for an example made when trying to compile up-imapproxy :
gcc -g -O2 -I. -I./include -c -o src/icc.o src/icc.c
gcc -g -O2 -I. -I./include -c -o src/main.o src/main.c
src/main.c: In function "int main(int, char**)":
src/main.c:618: error: invalid conversion from *void* to *void* (*)(void*)
src/main.c:618: error: initializing argument 3 of int pthread_create(pthread_t*, const pthread_attr_t*, void* (*)(void*), void*)
src/main.c:646: error: invalid conversion from int* to socklen_t*
src/main.c:646: error: initializing argument 3 of int accept(int, sockaddr*,socklen_t*)
src/main.c:675: error: invalid conversion from void* to void* (*)(void*)
src/main.c:675: error: initializing argument 3 of int pthread_create(pthread_t*, const pthread_attr_t*, void* (*)(void*), void*)
make: *** [src/main.o] Error 1