Hotspot developers has requested a way to quickly compile a subset of Hotspot files, to check for compilation errors.

Similar to JDK_FILTER, we should have a JVM_FILTER (or HOTSPOT_FILTER?) that, when set, limits the files included in the compilation. For instance,

make hotspot JVM_FILTER=z%

would only (re-)compile the ZGC files.

When this filter is set, no linking should be attempted. Make will return with a success error code (0) if the files matching the filter compiles successfully. After that, it will terminate. If any of the files cannot be compiled, make will return with an error code.