Add qemu support

see https://rt.perl.org/rt3//Public/Bug/Display.html?id=114798

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>

Index: b/Configure
===================================================================
--- a/Configure
+++ b/Configure
@@ -2837,6 +2837,9 @@
             ;;
         *)  echo "Using usrinc $usrinc." >&4 ;;
 	esac
+	case "$targetrun" in
+	*qemu*) targethost=dummy ;;
+	esac
 	case "$targethost" in
 	'') echo "Targethost not defined." >&4; croak=y ;;
         *)  echo "Using targethost $targethost." >&4
@@ -2868,7 +2871,7 @@
 	case "$targetfrom" in
 	'') targetfrom=scp ;;
 	esac
-    	run=$run-$targetrun
+    	run=$run-`basename $targetrun`
     	to=$to-$targetto
     	from=$from-$targetfrom
 	case "$targetdir" in
@@ -2908,6 +2911,14 @@
 $targetrun -l $targetuser $targethost "cd \$cwd && ./\$exe \$@"
 EOF
 	    ;;
+	*qemu*)
+	    to=:
+	    from=:
+	    cat >$run <<EOF
+#!/bin/sh
+$targetrun -L $qemulib "\$@"
+EOF
+	    ;;
 	*)  echo "Unknown targetrun '$targetrun'" >&4
 	    exit 1
 	    ;;
@@ -5048,7 +5059,7 @@
 echo " ";
 echo "Checking if your compiler accepts $flag" 2>&1;
 echo "int main(void) { return 0; }" > gcctest.c;
-if $cc -O2 $flag -o gcctest gcctest.c 2>gcctest.out && ./gcctest; then
+if $cc -O2 $flag -o gcctest gcctest.c 2>gcctest.out && $run ./gcctest; then
     echo "Yes, it does." 2>&1;
     if $test -s gcctest.out ; then
         echo "But your platform does not like it:";