A program which is linked or bound by reference (referenced program) into one or more other programs supports multiple valid export signatures, each corresponding to a respective version of the referenced program. When a program is built, it records the current signature of each referenced program it is bound to. When subsequently determining whether to rebuild the program, the previously recorded signature of any referenced program is compared with all currently supported signatures of the referenced program, and only if none of the supported signatures matches does the program need to be re-built to ensure compatibility with the referenced program. Preferably, the referenced program is a program library containing supporting procedures, intended to be used by multiple applications programs which are bound to it.