fix(build): Support glibc qualifiers for Rust targets (#1858)

If you're targetting an older Linux distro the default glibc version
being linked against may be too high to produce runnable images.

cargo zigbuild supports specifying a specific glibc version to use
for a link target by appending ".<version>" to the target triple.  For
example, "x86_64-unknown-linux-gnu.2.17" will target v2.17.

For the most part this just works but we need to strip this suffix when
looking for output binaries.  This fix adds that logic.

project/RustPlugin.scala

@@ -119,16 +119,18 @@ object RustPlugin extends AutoPlugin {
 
       // For each architecture find artifacts
       for (archTarget <- rustArchitectures.value) {
+        val normalizedArch = normalizeRustTarget(archTarget)
+
         // Special case - host
-        val archFolder = if (archTarget == "host") {
+        val archFolder = if (normalizedArch == "host") {
           targetFolder / releaseDir
         } else {
           // General case
-          targetFolder / archTarget / releaseDir
+          targetFolder / normalizedArch / releaseDir
         }
 
         // get os arch / kernel, build path
-        val resourceArchTarget = mapRustTargetToJVMTarget(archTarget)
+        val resourceArchTarget = mapRustTargetToJVMTarget(normalizedArch)
 
         // Find library files in folder
         // We place every produced library in a resource path like
@@ -207,6 +209,23 @@ object RustPlugin extends AutoPlugin {
     }
   }
 
+  // Normalize a target string by stripping excess info, like GLIBC version
+  private def normalizeRustTarget(target: String): String = {
+    // Handle strings like x86_64-unknown-linux-gnu.2.17,
+    // which contain a GLIBC version suffix
+    //
+    // We want to drop the suffix to get x86_64-unknown-linux-gnu
+    val RustPattern = "([^-]+)-([^-]+)-([^.]+).*".r
+
+    target match {
+      // Valid inputs
+      case "host" => target
+      case RustPattern(arch, vendor, kernel) => s"$arch-$vendor-$kernel"
+      // Not matched
+      case x => sys.error(s"Unsupported target $x")
+    }
+  }
+
   // Get normalized host kernel name
   private def getHostKernel: String = {
     if (SystemUtils.IS_OS_LINUX) {