Makedepend is a makefile dependency generator from The XFree86 Project, Inc. 
If you have X installed, you already have makedepend and do not need this port!

Makedepend reads each sourcefile in sequence and parses it like a 
C-preprocessor, processing all #include, #define, #undef, #ifdef, #ifndef, 
#endif, #if and #else directives so that it can correctly tell which #include, 
directives would be used in a compilation. Any #include, directives can 
reference files having other #include directives, and parsing will occur in 
these files as well.

Every file that a sourcefile includes, directly or indirectly, is what 
makedepend calls a "dependency". These dependencies are then written to a 
makefile in such a way that make will know which object files must be 
recompiled when a dependency has changed.

WWW: http://www.x.org/archive/X11R7.5/doc/man/man1/makedepend.1.html