This commit cleans up references to the old kubernetes-node-e2e-images
project. In the process it removes the `LIST_IMAGES` mode as listing
large numbers of public cloud projects is not particularly useful, and
has been somewhat broken for a long period of time - as we defaulted
launching a VM to a different project than listing.
Make's "define" feature (macros) is subtle and it took me a long time to
convince myself this all works. In particular, we (prior to this commit)
are terribly inconsistent about the use of `$` vs `$$`. We mostly get
away with it because the "variables" are more like "constants", but the
inconsistency trips up some things. For example, using `$(shell)`
inside a macro will run at macro expansion time rather than when the
resulting make code is executed.
For a contrived, but concrete example, derived from our Makefile:
```
define MACRO
ifeq ($(DBG),1)
$(warning dbg is $(DBG))
endif
endef # macro
TGTS=a b c
$(foreach pfx, $(TGTS), $(eval $(MACRO)))
default:
@echo $@
```
yields:
```
$ make
Makefile:8: dbg is
Makefile:8: dbg is
Makefile:8: dbg is
default
$ make DBG=1
Makefile:8: dbg is 1
Makefile:8: dbg is 1
Makefile:8: dbg is 1
default
```
This is because `$(warning)` is evaluated as the macro is expanded.
Replace that with `$(shell)` and you can see how you might end up
running a bunch of things you didn't need to run. The fix is:
```
define MACRO
ifeq ($(DBG),1)
$$(warning dbg is $$(DBG))
endif
endef # macro
TGTS=a b c
$(foreach pfx, $(TGTS), $(eval $(MACRO)))
default:
@echo $@
```
which yields:
```
$ make
default
$ make DBG=1
Makefile:8: dbg is 1
Makefile:8: dbg is 1
Makefile:8: dbg is 1
default
```
We COULD have only changed `$(warning)` to `$$(warning)` and left
`$(DBG)` alone, because that's a cheap expansion. I chose NOT to do
that here because it requires brainpower to think about this all, and it
seems easier to set a simple rule: inside a `define`/`endef` block, you
always use `$$` unless you KNOW that you NEED expansion-time evaluation
(as in the `$(prefix)` in this commit, which is effectively an argument
to the macros).
Only build and run go2make on the first pass. If that generates a new
GO_PKGDEPS_FILE, make will restart the whole process and set MAKE_RESTARTS to
a numeric value.
We can use this to avoid re-running go2make, which saves a few seconds
each build.
