Replace pir::find_caller_lex.

Author: jnthn

src/NQP/Grammar.pm

@@ -17,7 +17,7 @@ grammar NQP::Grammar is HLL::Grammar {
         # Serialization context builder - keeps track of objects that
         # cross the compile-time/run-time boundary that are associated
         # with this compilation unit.
-        my $file := pir::find_caller_lex__Ps('$?FILES');
+        my $file := nqp::getlexdyn('$?FILES');
         my $source_id := nqp::sha1(self.target()) ~
             (%*COMPILING<%?OPTIONS><stable-sc> ?? '' !! '-' ~ ~nqp::time_n());
         my $*W := nqp::isnull($file) ??

src/QAST/PIRT.nqp

@@ -205,7 +205,7 @@ class PIRT::Sub is PIRT::Node {
         nqp::push(@parts, $sub_decl);
         
         # File annotation, if there is one.
-        my $file := pir::find_caller_lex__Ps('$?FILES');
+        my $file := nqp::getlexdyn('$?FILES');
         if nqp::ifnull($file, '') {
             nqp::push(@parts, ".annotate 'file', " ~ self.escape($file));
         }