Since I've written a C compiler, I know how to read C source files. The problem with automated conversion is you can do 90% of the job without any trouble, but there's that darned last 10% that doesn't map to D without some human decision making.

For example, there are the preprocessor macros. Most are straightforward, but it seems most C .h files succumb to the temptation at some point to do something wacky with them.