Enable --target=pir to produce PIR code that can be run directly

from Parrot (provided Rakudo has been installed).

src/Perl6/Actions.pm

@@ -77,9 +77,12 @@ method comp_unit($/, $key?) {
     ));
 
     $unit.loadinit.unshift(
-        PAST::Op.new(
-            :name('!UNIT_OUTER'),
-            PAST::Var.new( :name('block'), :scope('register') )
+        PAST::Op.new( :pasttype<inline>,
+            :inline('    $P0 = find_name "!UNIT_OUTER"',
+                    '    unless null $P0 goto have_perl6',
+                    '    load_language "perl6"',
+                    '  have_perl6:',
+                    '    "!UNIT_OUTER"(block)')
         )
     );
 

src/Perl6/Compiler.pir

@@ -230,6 +230,17 @@ Perl6::Compiler - Perl6 compiler
     exit 0
 .end
 
+
+.sub 'pir' :method
+    .param pmc source
+    .param pmc adverbs         :slurpy :named
+    $P0 = compreg 'POST'
+    $S0 = $P0.'to_pir'(source, adverbs :flat :named)
+    $S0 = concat ".loadlib 'perl6_ops'\n", $S0
+    .return ($S0)
+.end
+
+
 .sub 'version' :method
     .local pmc interp, config, rev, version
     interp = getinterp