*Use a typedef rather than a macro definition for va_list. (The C standards specify that va_list is a type, although this would make a practical difference only if someone #undef'd it.)
*Don't include a semicolon in va_start(), so it expands to an expression rather than a statement. This could make a difference in a construct like "if (...) va_start(...); else ...".
In order to work right, this needs either GNO's ORCALib (which already included isblank()) or a copy of ORCA's ORCALib with the corresponding patch applied.
It had been changed to reflect changes in the ORCALib code that added a second putback buffer element, but those changes were problematic and have been reverted for now. (It's also not clear if ORCALib binaries with the larger putback buffer were ever distributed--at the least, they aren't on Opus ][ or in any of the ORCA/C 2.2.0 beta releases.)
The macro was slightly broken in that its 'buf' argument might be evaluated twice. This could be a problem if it was, e.g., a call to an allocation function.
This is needed to ensure correct behavior in cases where the macro is bypassed to access the library function, e.g. by enclosing the function name in parentheses or by taking its address.
