Added 'prebuild' target for users to run before build; this can be added to a...

Added 'prebuild' target for users to run before build; this can be added to a module.makefile to allow certain tasks to be run before the build process occurs.

App/tools/driver.makefile

@@ -125,6 +125,8 @@ ENV=
 # Don't install anything (different from default EPICS make rules).
 default: build
 
+prebuild:
+
 IGNOREFILES = .cvsignore .gitignore
 %: ${IGNOREFILES}
 ${IGNOREFILES}: