[[!meta  title="Make gotcha"]]
[[!meta  date="2008-08-31 18:47:36"]]
Alrighty, this one had me stumped for a while:

    $ cat Makefile
    DIRA=dirA
    DIRB =dirB
    DIRC = dirC
    DIRD=dirD# immediate comment
    DIRE= dirE# immediate comment
    DIRF=dirF
    DIRG=dirG # (dirF has a trailing space too)
    FILE = a  # more spaces here

    make : $(DIRA)/$(FILE) $(DIRB)/$(FILE) $(DIRC)/$(FILE) $(DIRD)/$(FILE) $(DIRE)/$(FILE) $(DIRF)/$(FILE) $(DIRG)/$(FILE)
            echo "done"
    % :
            echo "looking for $@"
    $ make
    looking for dirA/a
    looking for dirB/a
    looking for dirC/a
    looking for dirD/a
    looking for dirE/a
    looking for dirF
    looking for /a
    looking for dirG
    done

Apparently bonus whitespace (normally before a comment or after an
equals sign) in variable definitions is stripped from the front of a
definition, but not the back.  You have been warned ;).

[[!tag tags/programming]]