configure: generate Meson cross file

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -8630,21 +8630,75 @@ echo >> "$iotests_common_env"
 echo "export PYTHON='$python'" >> "$iotests_common_env"
 
 if test "$skip_meson" = no; then
+cross="config-meson.cross.new"
+meson_quote() {
+    echo "['$(echo $* | sed "s/ /','/g")']"
+}
+
+echo "# Automatically generated by configure - do not modify" > $cross
+echo "[properties]" >> $cross
+test -z "$cxx" && echo "link_language = 'c'" >> $cross
+echo "[binaries]" >> $cross
+echo "c = $(meson_quote $cc)" >> $cross
+test -n "$cxx" && echo "cpp = $(meson_quote $cxx)" >> $cross
+echo "ar = $(meson_quote $ar)" >> $cross
+echo "nm = $(meson_quote $nm)" >> $cross
+echo "pkgconfig = $(meson_quote $pkg_config_exe)" >> $cross
+echo "ranlib = $(meson_quote $ranlib)" >> $cross
+echo "strip = $(meson_quote $strip)" >> $cross
+echo "windres = $(meson_quote $windres)" >> $cross
+if test -n "$cross_prefix"; then
+    cross_arg="--cross-file config-meson.cross"
+    # Hack: Meson expects an absolute path for the *build* machine
+    # for the prefix, so add a slash in front of a Windows path that
+    # includes a drive letter.
+    #
+    # See https://github.com/mesonbuild/meson/issues/7577.
+    echo "[host_machine]" >> $cross
+    if test "$mingw32" = "yes" ; then
+        echo "system = 'windows'" >> $cross
+        case $prefix in
+            ?:*) pre_prefix=/ ;;
+        esac
+    fi
+    case "$ARCH" in
+        i386|x86_64)
+            echo "cpu_family = 'x86'" >> $cross
+            ;;
+        ppc64le)
+            echo "cpu_family = 'ppc64'" >> $cross
+            ;;
+        *)
+            echo "cpu_family = '$ARCH'" >> $cross
+            ;;
+    esac
+    echo "cpu = '$cpu'" >> $cross
+    if test "$bigendian" = "yes" ; then
+        echo "endian = 'big'" >> $cross
+    else
+        echo "endian = 'little'" >> $cross
+    fi
+else
+    cross_arg="--native-file config-meson.cross"
+fi
+mv $cross config-meson.cross
+
 rm -rf meson-private meson-info meson-logs
 NINJA=$PWD/ninjatool $meson setup \
-        --prefix "$prefix" \
+        --prefix "${pre_prefix}$prefix" \
-        --libdir "$libdir" \
+        --libdir "${pre_prefix}$libdir" \
-        --libexecdir "$libexecdir" \
+        --libexecdir "${pre_prefix}$libexecdir" \
-        --bindir "$bindir" \
+        --bindir "${pre_prefix}$bindir" \
-        --includedir "$includedir" \
+        --includedir "${pre_prefix}$includedir" \
-        --datadir "$datadir" \
+        --datadir "${pre_prefix}$datadir" \
-        --mandir "$mandir" \
+        --mandir "${pre_prefix}$mandir" \
-        --sysconfdir "$sysconfdir" \
+        --sysconfdir "${pre_prefix}$sysconfdir" \
-        --localstatedir "$local_statedir" \
+        --localstatedir "${pre_prefix}$local_statedir" \
         -Doptimization=$(if test "$debug" = yes; then echo 0; else echo 2; fi) \
         -Ddebug=$(if test "$debug_info" = yes; then echo true; else echo false; fi) \
         -Dwerror=$(if test "$werror" = yes; then echo true; else echo false; fi) \
         -Dstrip=$(if test "$strip_opt" = yes; then echo true; else echo false; fi) \
+        $cross_arg \
         "$PWD" "$source_path"
 
 if test "$?" -ne 0 ; then

meson.build

@@ -15,7 +15,12 @@ add_project_link_arguments(config_host['QEMU_LDFLAGS'].split(),
 add_project_arguments(config_host['QEMU_INCLUDES'].split(),
                       language: ['c', 'cpp', 'objc'])
 
-add_languages('cpp', required: false, native: false)
+python = import('python').find_installation()
+
+link_language = meson.get_external_property('link_language', 'cpp')
+if link_language == 'cpp'
+  add_languages('cpp', required: true, native: false)
+endif
 if host_machine.system() == 'darwin'
   add_languages('objc', required: false, native: false)
 endif