By the way, the original author of CLISP (a free Common Lisp implementation) liked mixed variables and statements so much that the C sources use a .d rather than .c suffix and are preprocessed to .c files through a text processing script called "varbrace" which turns mixed declarations and statements into C90.

That was long before C99; the project started around the middle 1980s, I think.

CLISP might benefit from being updated to C99, with all the files renamed to .c, and varbrace eliminated, but I don't think anyone's gotten around to it.