Create Native standalones by default for native* env files

* This used to be the case with just setting INSTALLABLES,
  but the addition of JVM standalones made all standalones opt-in.

Author: eregon

mx.truffleruby/native

@@ -5,3 +5,4 @@ NATIVE_IMAGES=suite:sulong,lib:rubyvm
 EXTRA_IMAGE_BUILDER_ARGUMENTS=rubyvm:-H:BuildOutputJSONFile=native-image-build-rubyvm.json
 # To also create the standalone
 INSTALLABLES=TruffleRuby
+BUILD_TARGETS=GRAALVM,GRAALVM_STANDALONES

mx.truffleruby/native-ee

@@ -5,3 +5,4 @@ NATIVE_IMAGES=suite:sulong,lib:rubyvm
 EXTRA_IMAGE_BUILDER_ARGUMENTS=rubyvm:-H:BuildOutputJSONFile=native-image-build-rubyvm.json
 # To also create the standalone
 INSTALLABLES=TruffleRuby
+BUILD_TARGETS=GRAALVM,GRAALVM_STANDALONES

mx.truffleruby/native-ee-aux

@@ -6,3 +6,4 @@ EXTRA_IMAGE_BUILDER_ARGUMENTS=rubyvm:-H:BuildOutputJSONFile=native-image-build-r
 NATIVE_IMAGE_AUXILIARY_ENGINE_CACHE=true
 # To also create the standalone
 INSTALLABLES=TruffleRuby
+BUILD_TARGETS=GRAALVM,GRAALVM_STANDALONES

mx.truffleruby/native-host-inlining

@@ -5,3 +5,4 @@ NATIVE_IMAGES=lib:rubyvm
 EXTRA_IMAGE_BUILDER_ARGUMENTS=rubyvm:-H:BuildOutputJSONFile=native-image-build-rubyvm.json rubyvm:-H:Log=HostInliningPhase,~CanonicalizerPhase,~GraphBuilderPhase rubyvm:-H:+TruffleHostInliningPrintExplored rubyvm:-Dgraal.LogFile=host-inlining.txt
 # To also create the standalone
 INSTALLABLES=TruffleRuby
+BUILD_TARGETS=GRAALVM,GRAALVM_STANDALONES

tool/make-standalone-distribution.sh

@@ -10,7 +10,7 @@ set -e
 set -x
 
 # Build
-bin/jt build --env native -- --targets=GRAALVM_STANDALONES
+bin/jt build --env native
 
 standalone=$(bin/jt mx --env native standalone-home ruby)
 release_home="$PWD/mxbuild/truffleruby-standalone"