Build fat binary for arm64 and x86_64 on MacOS in build.sbt

[eatkins]

This PR reworks #11 so that we build a fat binary for osx that includes both arm64 and x86_64 code. It also adds the logic to the build.sbt to build the multi-arch version so that we can easily create new binaries in the future.

[joan38]

Hi @eatkins and @eed3si9n, I'm trying to make mill work with Apple's arm64 and we have a dependency on this lib.
I upgraded to 1.3.0 but I'm still getting this error:

Exception in thread "main" java.lang.UnsatisfiedLinkError: /Users/jgoyeau/Library/Caches/JNA/temp/jna10824615888576569736.tmp: dlopen(/Users/jgoyeau/Library/Caches/JNA/temp/jna10824615888576569736.tmp, 1): no suitable image found.  Did find:
        /Users/jgoyeau/Library/Caches/JNA/temp/jna10824615888576569736.tmp: no matching architecture in universal wrapper
        /Users/jgoyeau/Library/Caches/JNA/temp/jna10824615888576569736.tmp: no matching architecture in universal wrapper
        at java.base/java.lang.ClassLoader$NativeLibrary.load0(Native Method)
        at java.base/java.lang.ClassLoader$NativeLibrary.load(ClassLoader.java:2442)
        at java.base/java.lang.ClassLoader$NativeLibrary.loadLibrary(ClassLoader.java:2498)
        at java.base/java.lang.ClassLoader.loadLibrary0(ClassLoader.java:2694)
        at java.base/java.lang.ClassLoader.loadLibrary(ClassLoader.java:2627)
        at java.base/java.lang.Runtime.load0(Runtime.java:768)
        at java.base/java.lang.System.load(System.java:1837)
        at com.sun.jna.Native.loadNativeDispatchLibraryFromClasspath(Native.java:1018)
        at com.sun.jna.Native.loadNativeDispatchLibrary(Native.java:988)
        at com.sun.jna.Native.<clinit>(Native.java:195)
        at org.scalasbt.ipcsocket.UnixDomainSocketLibrary.<clinit>(UnixDomainSocketLibrary.java:129)
        at org.scalasbt.ipcsocket.JNAUnixDomainSocketLibraryProvider.socket(UnixDomainSocketLibrary.java:165)
        at org.scalasbt.ipcsocket.UnixDomainServerSocket.<init>(UnixDomainServerSocket.java:109)
        at org.scalasbt.ipcsocket.UnixDomainServerSocket.<init>(UnixDomainServerSocket.java:87)
        at mill.main.Server.$anonfun$run$2(MillServerMain.scala:89)
        at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
        at mill.main.Server$.lockBlock(MillServerMain.scala:201)
        at mill.main.Server.$anonfun$run$1(MillServerMain.scala:82)
        at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
        at mill.main.Server$.tryLockBlock(MillServerMain.scala:208)
        at mill.main.Server.run(MillServerMain.scala:79)
        at mill.main.MillServerMain$.main(MillServerMain.scala:43)
        at mill.main.MillServerMain.main(MillServerMain.scala)

I was wondering if by any chance you had any hints? Are we supposed to change our usage of the lib to take advantage of this change?
Thanks

[eed3si9n]

I don't think there's JNA for ARM Macs.

[eatkins]

There is a JNI implementation that targets arm64 on osx but you have to change your code to optionally use it. JNI isn't supported on all platforms so you will probably have to handle the logic for platform detection yourself.

ipcsocket/src/main/java/org/scalasbt/ipcsocket/UnixDomainServerSocket.java

Line 91 in d5e67af

public UnixDomainServerSocket(String path, boolean useJNI) throws IOException {

[joan38]

Are you talking about the boolean useJNI parameter? Because we are currently passing false all the time.
We are using this constructor:

ipcsocket/src/main/java/org/scalasbt/ipcsocket/UnixDomainServerSocket.java

Lines 86 to 87 in d5e67af

	public UnixDomainServerSocket(String path) throws IOException {
	this(DEFAULT_BACKLOG, path, false);

[joan38]

Ah I see, you mean I need to pass JNI true there.
I tried and now I'm one step further hitting:

Exception in thread "MillServerActionRunner" java.lang.NoClassDefFoundError: Could not initialize class org.scalasbt.ipcsocket.UnixDomainSocketLibrary
        at org.scalasbt.ipcsocket.JNAUnixDomainSocketLibraryProvider.write(UnixDomainSocketLibrary.java:247)
        at org.scalasbt.ipcsocket.UnixDomainSocket$UnixDomainSocketOutputStream.doWrite(UnixDomainSocket.java:185)
        at org.scalasbt.ipcsocket.UnixDomainSocket$UnixDomainSocketOutputStream.write(UnixDomainSocket.java:169)

It's like if the UnixDomainSocketLibraryProvider.get(useJNI) gives me JNAUnixDomainSocketLibraryProvider.instance() instead of JNIUnixDomainSocketLibraryProvider.instance().

[eatkins]

You also need to set the JNI parameter when constructing the UnixDomainSocket not just the UnixDomainServerSocket.