Improve nixos support for recent protoc versions

bridge/src/main/scala/protocbridge/ProtocRunner.scala

@@ -57,10 +57,19 @@ object ProtocRunner {
         None
     }
 
+  // This version of maybeNixDynamicLinker() finds ld-linux and also uses it
+  // to verify that the executable is dynamic. Newer version (>=3.23.0) of
+  // protoc are static, and thus do not load with ld-linux.
+  def maybeNixDynamicLinker(executable: String): Option[String] =
+    maybeNixDynamicLinker().filter { linker =>
+      Process(command = Seq(linker, "--verify", executable)).! == 0
+    }
+
   def apply(executable: String): ProtocRunner[Int] = ProtocRunner.fromFunction {
     case (args, extraEnv) =>
       Process(
-        command = (maybeNixDynamicLinker().toSeq :+ executable) ++ args,
+        command =
+          (maybeNixDynamicLinker(executable).toSeq :+ executable) ++ args,
         cwd = None,
         extraEnv: _*
       ).!

protoc-cache-coursier/src/main/scala/protocbridge/ProtocCacheCoursier.scala

@@ -5,7 +5,6 @@ import java.io.File
 import scala.concurrent.ExecutionContext.Implicits.global
 import scala.concurrent.Await
 import scala.concurrent.duration.Duration
-import scala.io.Source
 import coursier._
 import coursier.core.Extension
 
@@ -23,13 +22,10 @@ object CoursierProtocCache {
   ): Int = {
     import sys.process._
 
-    val maybeNixDynamicLinker: Option[String] =
-      sys.env.get("NIX_CC").map { nixCC =>
-        Source.fromFile(nixCC + "/nix-support/dynamic-linker").mkString.trim()
-      }
+    val protoc = getProtoc(version).getAbsolutePath()
 
-    val cmd = (maybeNixDynamicLinker.toSeq :+ getProtoc(version)
-      .getAbsolutePath()) ++ args
+    val cmd =
+      (ProtocRunner.maybeNixDynamicLinker(protoc).toSeq :+ protoc) ++ args
     Process(command = cmd, cwd = None, extraEnv: _*).!
   }