configure: allow configuring localedir

Meson has a localedir option, so passing the path through that option
is the cleanest way when we move directories out of config-host.mak.
In preparation for doing that without changing semantics and without
special-casing localedir code, add a configure option.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -962,6 +962,8 @@ for opt do
   ;;
   --docdir=*) docdir="$optarg"
   ;;
+  --localedir=*) localedir="$optarg"
+  ;;
   --sysconfdir=*) sysconfdir="$optarg"
   ;;
   --localstatedir=*) local_statedir="$optarg"
@@ -971,7 +973,7 @@ for opt do
   --host=*|--build=*|\
   --disable-dependency-tracking|\
   --sbindir=*|--sharedstatedir=*|\
-  --oldincludedir=*|--datarootdir=*|--infodir=*|--localedir=*|\
+  --oldincludedir=*|--datarootdir=*|--infodir=*|\
   --htmldir=*|--dvidir=*|--pdfdir=*|--psdir=*)
     # These switches are silently ignored, for compatibility with
     # autoconf-generated configure scripts. This allows QEMU's
@@ -1525,6 +1527,7 @@ firmwarepath="${firmwarepath:-$prefix/share/qemu-firmware}"
 libdir="${libdir:-$prefix/lib}"
 libexecdir="${libexecdir:-$prefix/libexec}"
 includedir="${includedir:-$prefix/include}"
+localedir="${localedir:-$datadir/locale}"
 
 if test "$mingw32" = "yes" ; then
     mandir="$prefix"
@@ -1670,6 +1673,7 @@ Advanced options (experts only):
   --static                 enable static build [$static]
   --mandir=PATH            install man pages in PATH
   --datadir=PATH           install firmware in PATH/$qemu_suffix
+  --localedir=PATH         install translation in PATH/$qemu_suffix
   --docdir=PATH            install documentation in PATH/$qemu_suffix
   --bindir=PATH            install binaries in PATH
   --libdir=PATH            install libraries in PATH
@@ -5728,7 +5732,6 @@ fi
 qemu_confdir="$sysconfdir/$qemu_suffix"
 qemu_moddir="$libdir/$qemu_suffix"
 qemu_datadir="$datadir/$qemu_suffix"
-qemu_localedir="$datadir/locale"
 qemu_icondir="$datadir/icons"
 qemu_desktopdir="$datadir/applications"
 
@@ -5912,7 +5915,7 @@ if test "$mingw32" = "no" ; then
   echo "qemu_localstatedir=$local_statedir" >> $config_host_mak
 fi
 echo "qemu_helperdir=$libexecdir" >> $config_host_mak
-echo "qemu_localedir=$qemu_localedir" >> $config_host_mak
+echo "qemu_localedir=$localedir" >> $config_host_mak
 echo "qemu_icondir=$qemu_icondir" >> $config_host_mak
 echo "qemu_desktopdir=$qemu_desktopdir" >> $config_host_mak
 echo "GIT=$git" >> $config_host_mak