def linuxLastTagIds = GetLastTagIds(linuxRepo, linuxBranchesOfInterest)
// Load previously built Linux tag ids.
println("Loading Git object IDs of previously built projects from the workspace.");
def oldLinuxTags = LoadPreviousIdsFromWorkspace(linuxOnDiskPath) as Set
def linuxLastTagIds = GetLastTagIds(linuxRepo, linuxBranchesOfInterest)
// Load previously built Linux tag ids.
println("Loading Git object IDs of previously built projects from the workspace.");
def oldLinuxTags = LoadPreviousIdsFromWorkspace(linuxOnDiskPath) as Set