why Apache compile with system's cc

I want to know why Apache compile with system's cc?

If the server won't compile on your system, it is probably due to one of the following reasons:

Your system environment doesn't recognizes the configure script.

This might be either because it's completely unknown or the specific environment (include files, OS version, etc) isn't explicitly handled. If this happens, you may need to port the server to your OS yourself.

Another reason may also be that your system's C compiler is garbage.

Some operating systems include a default C compiler that is either not ANSI C-compliant or suffers from other deficiencies.

The usual recommendation in cases like this is to acquire, install, and use gcc.

I also encounter the same problem.

In my cases, I found that a compiler installation had left the C header files in an inconsistent state.

Make sure that your include directory tree is in sync with the compiler and the operating system.

Your operating system or compiler may be out of revision. Try upgrading your compiler and/or your operating system.