Do not use $SHELL to invoke our scripts

http://www.opengroup.org/onlinepubs/7990989775/xbd/envvar.html

<quote>
SHELL
    A pathname of the user's preferred command language
    interpreter. If this interpreter does not conform to the XSI Shell
    Command Language in the XCU specification, Shell Command Language,
    utilities may behave differently from those described in this
    specification set.
</quote>

So using shells for users who prefer csh variants is a no go.

configure

@@ -15,6 +15,8 @@ TMPC="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}.c"
 TMPO="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}.o"
 TMPE="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}"
 
+THISSHELL=${_:-/bin/sh}
+
 trap "rm -f $TMPC $TMPO $TMPE ; exit" 0 2 3 15
 
 compile_object() {
@@ -1795,7 +1797,7 @@ echo "EXESUF=$EXESUF" >> $config_host_mak
 
 echo "/* Automatically generated by configure - do not modify */" > $config_host_h
 
-$SHELL $source_path/create_config < $config_host_mak >> $config_host_h
+$THISSHELL $source_path/create_config < $config_host_mak >> $config_host_h
 
 if test -f ${config_host_h}~ ; then
   if cmp -s $config_host_h ${config_host_h}~ ; then
@@ -2215,7 +2217,7 @@ echo "QEMU_CFLAGS+=$cflags" >> $config_mak
 echo "/* Automatically generated by configure - do not modify */" > $config_h
 echo "#include \"../config-host.h\"" >> $config_h
 
-$SHELL $source_path/create_config < $config_mak >> $config_h
+$THISSHELL $source_path/create_config < $config_mak >> $config_h
 
 if test -f ${config_h}~ ; then
   if cmp -s $config_h ${config_h}~ ; then