In the past a very low effort interface was used:
- All parmeters were treated as though they were type uinptr_t, and
- The maximum number of parmeters (6) was passed in all cases.
The first is potentially wrong and the second is very inefficient. This commit improves this by:
- Making tools/mksyscall.c more intelligent, and
- Extending the syntax for variadic functions.
For example, in syscall.cvs, the open() API was represened like this:
"open","fcntl.h","","int","const char*","int","..."
In reality, open may take only a single optional argument of type mode_t which is not the same size as uintptr_t. And there is not reason to pass 6 parameters in that case.
And this has been extended to:
"open","fcntl.h","","int","const char*","int","...","mode_t"
The existence of the "mode_t" tells tools/mksyscall that there is at most one optional parameter and, if present, it is of type mode_t.
