I have installed the developer tools, but I'm still having a problem when trying to compile any programs. Here is an example from when I tried apache 1.3.20:
regcomp.c:1: header file 'sys/types.h' not found
regcomp.c:2: header file 'stdio.h' not found
regcomp.c:3: header file 'string.h' not found
regcomp.c:4: header file 'ctype.h' not found
regcomp.c:5: header file 'limits.h' not found
regcomp.c:6: header file 'stdlib.h' not found
They dont appear to be anywhere on the system, either. Did I not install the complete Developer's Tools?