Stop using the bootclasspath for Java 9 compatibility

It's no longer introspectable under Java 9. The scalac 2.12 shell scripts work
around this by passing the bootclasspath jars as an additional system
property, but we can avoid this complication by just using -classpath instead.
This may have a slight negative impact on startup performance since the
JVM bytecode verifier is not run for classes from the bootclasspath, but
we can worry about that later.

Author: smarter

bench/src/main/scala/Benchmarks.scala

@@ -37,7 +37,7 @@ object Bench {
     val libs = System.getProperty("BENCH_CLASS_PATH")
 
     val opts = new OptionsBuilder()
-               .jvmArgsPrepend("-Xbootclasspath/a:" + libs + ":")
+               .jvmArgsPrepend("-classpath " + libs + ":")
                .mode(Mode.AverageTime)
                .timeUnit(TimeUnit.MILLISECONDS)
                .warmupIterations(warmup)

dist/bin/dotc

@@ -28,7 +28,6 @@ fi
 source "$PROG_HOME/bin/common"
 
 default_java_opts="-Xmx768m -Xms768m"
-bootcp=true
 
 CompilerMain=dotty.tools.dotc.Main
 FromTasty=dotty.tools.dotc.FromTasty
@@ -64,11 +63,7 @@ classpathArgs () {
   toolchain+="$DOTTY_LIB$PSEP"
   toolchain+="$DOTTY_COMP"
 
-  if [[ -n "$bootcp" ]]; then
-    jvm_cp_args="-Xbootclasspath/a:\"$toolchain\""
-  else
-    jvm_cp_args="-classpath \"$toolchain\""
-  fi
+  jvm_cp_args="-classpath \"$toolchain\""
 }
 
 while [[ $# -gt 0 ]]; do
@@ -85,8 +80,6 @@ case "$1" in
        -tasty) PROG_NAME="$FromTasty" && shift ;;
      -compile) PROG_NAME="$CompilerMain" && shift ;;
          -run) PROG_NAME="$ReplMain" && shift ;;
-      -bootcp) bootcp=true && shift ;;
-   -nobootcp) unset bootcp && shift ;;
       -colors) colors=true && shift ;;
    -no-colors) unset colors && shift ;;
 

project/Build.scala

@@ -613,7 +613,7 @@ object Build {
             path.contains("scala-asm") ||
             // needed for the xsbti interface
             path.contains("sbt-interface")
-        } yield "-Xbootclasspath/p:" + path
+        } yield "-classpath " + path
 
         val ci_build = // propagate if this is a ci build
           if (sys.props.isDefinedAt(JENKINS_BUILD))