Makefile: All images are tested. Remove ALL_IMAGES and DEFAULT_IMAGES vars.

To confirm that the Makefiles works as expected after this patch, the
list of executed commands before and after has been compared.

Before:

```
make --dry-run > ../dockcross-make-baseline
make test --dry-run > ../dockcross-make-test-baseline
```

After:

```
make --dry-run > ../dockcross-make-current;
make test --dry-run > ../dockcross-make-test-current

for target in make make-test; do
  diff --ignore-trailing-space ../dockcross-$target-baseline ../dockcross-$target-current> /dev/null 2>&1
  [[ $? == 1 ]] && \
    echo "" && \
    echo "-------------------------------" && \
    echo "Here is output of:" && \
    echo "  diff --ignore-trailing-space ../dockcross-$target-baseline ../dockcross-$target-current" && \
    echo "" && \
    diff --ignore-trailing-space ../dockcross-$target-baseline ../dockcross-$target-current
done
```

Output:

```
-------------------------------
Here is output of:
  diff --ignore-trailing-space ../dockcross-make-baseline ../dockcross-make-current

8a9
> docker build -t dockcross/linux-ppc64le linux-ppc64le
10a12,14
> cp -r test browser-asmjs/
> docker build -t dockcross/browser-asmjs browser-asmjs
> rm -rf browser-asmjs/test

-------------------------------
Here is output of:
  diff --ignore-trailing-space ../dockcross-make-test-baseline ../dockcross-make-test-current

24a25,27
> docker build -t dockcross/linux-ppc64le linux-ppc64le
> docker run --rm dockcross/linux-ppc64le > bin/dockcross-linux-ppc64le && chmod +x bin/dockcross-linux-ppc64le
> bin/dockcross-linux-ppc64le python test/run.py --languages C
30a34,38
> cp -r test browser-asmjs/
> docker build -t dockcross/browser-asmjs browser-asmjs
> rm -rf browser-asmjs/test
> docker run --rm dockcross/browser-asmjs > bin/dockcross-browser-asmjs && chmod +x bin/dockcross-browser-asmjs
> bin/dockcross-browser-asmjs python test/run.py --exe-suffix ".js"

```

Makefile

@@ -19,10 +19,7 @@ STANDARD_IMAGES = android-arm linux-x86 linux-x64 linux-arm64 linux-armv5 linux-
 NON_STANDARD_IMAGES = browser-asmjs manylinux-x64 manylinux-x86
 
 # This list all available images
-ALL_IMAGES = $(STANDARD_IMAGES) $(NON_STANDARD_IMAGES)
+IMAGES = $(STANDARD_IMAGES) $(NON_STANDARD_IMAGES)
-
-# Set DEFAULT_IMAGES by excluding experimental images from ALL_IMAGES
-DEFAULT_IMAGES = $(filter-out browser-asmjs linux-ppc64le, $(ALL_IMAGES))
 
 # Optional arguments for test runner (test/run.py) associated with "testing implicit rule"
 linux-ppc64le.test_ARGS = --languages C
@@ -30,14 +27,14 @@ windows-x86.test_ARGS = --exe-suffix ".exe"
 windows-x64.test_ARGS = --exe-suffix ".exe"
 
 #
-# images: This target builds all DEFAULT_IMAGES (because it is the first one, it is built by default)
+# images: This target builds all IMAGES (because it is the first one, it is built by default)
 #
-images: base $(DEFAULT_IMAGES)
+images: base $(IMAGES)
 
 #
 # test: This target ensures all IMAGES are built and run the associated tests
 #
-test: base.test $(addsuffix .test,$(DEFAULT_IMAGES))
+test: base.test $(addsuffix .test,$(IMAGES))
 
 #
 # browser-asmjs
@@ -93,13 +90,10 @@ base.test: base
 #
 # display
 #
-display_default_images:
+display_images:
-	for image in $(DEFAULT_IMAGES); do echo $$image; done
+	for image in $(IMAGES); do echo $$image; done
 
-display_all_images:
+$(VERBOSE).SILENT: display_images
-	for image in $(ALL_IMAGES); do echo $$image; done
-
-$(VERBOSE).SILENT: display_default_images display_all_images
 
 #
 # build implicit rule
@@ -115,4 +109,4 @@ $(addsuffix .test,$(STANDARD_IMAGES)): $$(basename $$@)
 	$(DOCKER) run --rm dockcross/$(basename $@) > $(BIN)/dockcross-$(basename $@) && chmod +x $(BIN)/dockcross-$(basename $@)
 	$(BIN)/dockcross-$(basename $@) python test/run.py $($@_ARGS)
 
-.PHONY: base images $(ALL_IMAGES) test %.test
+.PHONY: base images $(IMAGES) test %.test

README.rst

@@ -183,11 +183,10 @@ source cross-compiler Docker image or the dockcross script itself.
 Download all images
 -------------------
 
-To easily download all images, the convenience target ``display_all_images`` or ``display_default_images``
+To easily download all images, the convenience target ``display_images`` could be used::
-could be used::
 
   curl https://raw.githubusercontent.com/dockcross/dockcross/master/Makefile -o dockcross-Makefile
-  for image in $(make -f dockcross-Makefile display_all_images); do
+  for image in $(make -f dockcross-Makefile display_images); do
     echo "Pulling dockcross/$image"
     docker pull dockcross/$image
   done
@@ -196,10 +195,10 @@ Install all dockcross scripts
 -----------------------------
 
 To automatically install in ``~/bin`` the dockcross scripts for each images already downloaded, the
-convenience target ``display_all_images`` or ``display_default_images`` could be used::
+convenience target ``display_images`` could be used::
 
   curl https://raw.githubusercontent.com/dockcross/dockcross/master/Makefile -o dockcross-Makefile
-  for image in $(make -f dockcross-Makefile display_all_images); do
+  for image in $(make -f dockcross-Makefile display_images); do
     if [[ $(docker images -q dockcross/$image) == "" ]]; then
       echo "~/bin/dockcross-$image skipping: image not found locally"
       continue