Isn't it common knowledge that c89 has implicit function declarations? Here the the relevant standard quote: If the expression that precedes the parenthe

Isn't it common knowledge that c89 has implicit function declarations? Here the the relevant standard quote: If the expression that precedes the parenthesized argument list in a function call consists solely of an identifier, and if no declaration is visible for this identifier, the identifier is implicitly declared exactly as if, in the innermost block containing the function call, the declaration extern int identifier(); appeared