Add nqp::x_posixerrno

Author: hoelzro

src/QAST/Operations.nqp

@@ -1740,6 +1740,7 @@ QAST::Operations.add_core_pirop_mapping('tonum_I', 'nqp_bigint_to_num', 'NP', :i
 QAST::Operations.add_core_pirop_mapping('buildnativecall', 'nqp_native_call_build', 'vPsssPP');
 QAST::Operations.add_core_pirop_mapping('nativecall', 'nqp_native_call', 'PPPP');
 QAST::Operations.add_core_pirop_mapping('nativecallrefresh', 'nqp_native_call_wb', 'vP');
+QAST::Operations.add_core_pirop_mapping('x_posixerrno', 'nqp_posixerrno', 'I');
 
 # boolean opcodes
 QAST::Operations.add_core_pirop_mapping('not_i', 'not', 'Ii', :inlinable(1));

src/ops/nqp.ops

@@ -1,5 +1,7 @@
 BEGIN_OPS_PREAMBLE
 
+#include <errno.h>
+
 /* Parroty includes. */
 #include "parrot/parrot.h"
 #include "parrot/extend.h"
@@ -2906,6 +2908,19 @@ inline op nqp_fresh_stub(out PMC, invar PMC) :base_core {
 
 /*
 
+=item nqp_posixerrno
+
+Returns the value of errno.
+
+=cut
+
+*/
+inline op nqp_posixerrno(out INT) :base_core {
+    $1 = errno;
+}
+
+/*
+
 =item captureposprimspec
 
 Takes a CallContext in $2 and an index in $3, and returns the primitive