The main changes made to most tests are:
*Declarations always include explicit types, not relying on implicit int. The declaration of main in most test programs is changed to be "int main (void) {...}", adding an explicit return type and a prototype. (There are still some non-prototyped functions, though.)
*Functions are always declared before use, either by including a header or by providing a declaration for the specific function. The latter approach is usually used for printf, to avoid requiring ORCA/C to process stdio.h when compiling every test case (which might make test runs noticeably slower).
*Make all return statements in non-void functions (e.g. main) return a value.
*Avoid some instances of undefined behavior and type errors in printf and scanf calls.
Several miscellaneous bugs are also fixed.
There are still a couple test cases that intentionally rely on the C89 behavior, to ensure it still works.
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