configure: Avoid use of 'local' as it is non-POSIX

We use the non-POSIX 'local' keyword in just two places in configure;
rewrite to avoid it.

In do_compiler(), just drop the 'local' keyword.  The variable
'compiler' is only used elsewhere in the do_compiler_werror()
function, which already uses the variable as a normal non-local one.

In probe_target_compiler(), $try and $t are both local; make them
normal variables and use a more obviously distinct variable name
for $t.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20220825150703.4074125-8-peter.maydell@linaro.org

configure

@@ -110,7 +110,7 @@ error_exit() {
 do_compiler() {
   # Run the compiler, capturing its output to the log. First argument
   # is compiler binary to execute.
-  local compiler="$1"
+  compiler="$1"
   shift
   if test -n "$BASH_VERSION"; then eval '
       echo >>config.log "
@@ -2065,7 +2065,6 @@ probe_target_compiler() {
     : ${container_cross_strip:=${container_cross_prefix}strip}
   done
 
-  local t try
   try=cross
   case "$target_arch:$cpu" in
     aarch64_be:aarch64 | \
@@ -2078,8 +2077,8 @@ probe_target_compiler() {
       try='native cross' ;;
   esac
   eval "target_cflags=\${cross_cc_cflags_$target_arch}"
-  for t in $try; do
-    case $t in
+  for thistry in $try; do
+    case $thistry in
     native)
       target_cc=$cc
       target_ccas=$ccas