CTL just copy pastes a bunch of code via an include for each new type. The following two tidbits are basically the same thing:

CTL

    #define P 
    #define T int
    #include <vec.h>

STL

    #include <vector>
    template class std::vector<int>;

C++ with its STL is just dramatically slower at compiling it all. C loves to chew through its basic syntax and O(1) lookup since every symbol is essentially unique (take that C++ and your function overloading!)