linux - GNU make - making one task do another task as well -

here makefile:

z :     echo "redoing z" ; touch z  : b b2     touch     touch a2     touch z # should disable z doesn't  b : c c2     touch b     touch b2 

when make a, z touched twice, want touched once, how do that?

the targets , recipes in disconnect here: recipes should produce targets, not other targets. e.g.:

z :     touch z  : b b2     touch  b : c c2     touch b  # add rules b2, c , c2