* module/language/c99/compiler.mes (expr->accu): pointer arithmetic with pointer-variable.
* scaffold/tests/76-pointer-arithmetic.c (test): Test it.
* mlibc/include/stdarg.h (va_start): Update for fixed pointer arithmetic.
* module/language/c99/compiler.mes (expr->accu): Support pointer
arithmetic with variable: p + i, p - i, p += i, p -= i.
* scaffold/tests/76-pointer-arithmetic.c (test): Test it.
* module/language/c99/compiler.mes (expr->accu): Remove specific --/++.
(expr->accu*): Support p, *p.
* scaffold/tests/76-pointer-arithmetic.c (test): Test it.
* module/language/c99/compiler.mes (ident->size, expr->size): New function.
(expr->accu): Use them for ++,--,add, sub.
(i386:type-alist): Set void size to 1.
* scaffold/tests/71-struct-array.c (test):
* scaffold/tests/76-pointer-arithmetic.c: Test it.
* make.scm (add-scaffold-test): Build it.
