Understanding objc.test

[akim]

I don't understand the test objc.test (which fails with one of the
patches I work on).


    # Test to make sure LINK defined for Objective C.
    echo 'AC_SUBST(OBJC)' >> configure.in
    
    cat > Makefile.am << 'END'
    bin_PROGRAMS = foo
    foo_SOURCES = foo.m
    
    SUFFIXES = .m
    .m.o:
            whatever
    END
    
    $AUTOMAKE || exit 1
    
    grep '^LINK' Makefile.in


I don't understand why $(LINK) should be (and was) defined.
automake.in says:

    # `-pure' is `yes' or `no'.  A `pure' language is one where, if
    # all the files in a directory are of that language, then we do
    # not require the C compiler or any code to call it.

and

&register_language ('objc', 'linker=OBJCLINK', 'autodep=OBJC',
                    'flags=OBJCFLAGS',
                    'compile=$(OBJC) $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) 
$(AM_OBJCFLAGS) $(OBJCFLAGS)',
                    'compiler-name=OBJCCOMPILE',
                    'output-arg=-c -o $@',
                    'pure=yes',
                    'm');


so it seems to me that there are no reason for LINK to be defined
here.  What is it that I missed?