WHen libyaml is not installed, make fails with the following cryptic
message:
```
gmake[2]: Entering directory '/home/chkbuild/chkbuild-crossruby/tmp/build/20220325T045825Z/ruby/ext/psych'
gmake[2]: *** No rule to make target 'yaml/yaml.h', needed by 'psych.o'. Stop.
gmake[2]: Leaving directory '/home/chkbuild/chkbuild-crossruby/tmp/build/20220325T045825Z/ruby/ext/psych'
```
I think it should give up building psych with a clear message.
ca85f16a7d