ui: better unicode support for curses, v2.

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Merge remote-tracking branch 'remotes/kraxel/tags/ui-20190313-pull-request' into staging

ui: better unicode support for curses, v2.

# gpg: Signature made Wed 13 Mar 2019 07:29:44 GMT
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/ui-20190313-pull-request:
  curses: add option to specify VGA font encoding
  iconv: detect and make curses depend on it

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

configure

@@ -1224,6 +1224,10 @@ for opt do
   ;;
   --enable-curses) curses="yes"
   ;;
+  --disable-iconv) iconv="no"
+  ;;
+  --enable-iconv) iconv="yes"
+  ;;
   --disable-curl) curl="no"
   ;;
   --enable-curl) curl="yes"
@@ -1713,6 +1717,7 @@ disabled with --disable-FEATURE, default is enabled if available:
   gtk             gtk UI
   vte             vte support for the gtk UI
   curses          curses UI
+  iconv           font glyph conversion support
   vnc             VNC UI support
   vnc-sasl        SASL encryption for VNC server
   vnc-jpeg        JPEG lossy compression for VNC server
@@ -3434,8 +3439,52 @@ EOF
   fi
 fi
 
+##########################################
+# iconv probe
+if test "$iconv" != "no" ; then
+  cat > $TMPC << EOF
+#include <iconv.h>
+int main(void) {
+  iconv_t conv = iconv_open("WCHAR_T", "UCS-2");
+  return conv != (iconv_t) -1;
+}
+EOF
+  iconv_prefix_list="/usr/local:/usr"
+  iconv_lib_list=":-liconv"
+  IFS=:
+  for iconv_prefix in $iconv_prefix_list; do
+    IFS=:
+    iconv_cflags="-I$iconv_prefix/include"
+    iconv_ldflags="-L$iconv_prefix/lib"
+    for iconv_link in $iconv_lib_list; do
+      unset IFS
+      iconv_lib="$iconv_ldflags $iconv_link"
+      echo "looking at iconv in '$iconv_cflags' '$iconv_lib'" >> config.log
+      if compile_prog "$iconv_cflags" "$iconv_lib" ; then
+        iconv_found=yes
+        break
+      fi
+    done
+    if test "$iconv_found" = yes ; then
+      break
+    fi
+  done
+  if test "$iconv_found" = "yes" ; then
+    iconv=yes
+  else
+    if test "$iconv" = "yes" ; then
+      feature_not_found "iconv" "Install iconv devel"
+    fi
+    iconv=no
+  fi
+fi
+
 ##########################################
 # curses probe
+if test "$iconv" = "no" ; then
+  # curses will need iconv
+  curses=no
+fi
 if test "$curses" != "no" ; then
   if test "$mingw32" = "yes" ; then
     curses_inc_list="$($pkg_config --cflags ncurses 2>/dev/null):"
@@ -3449,14 +3498,17 @@ if test "$curses" != "no" ; then
 #include <locale.h>
 #include <curses.h>
 #include <wchar.h>
+#include <langinfo.h>
 int main(void) {
+  const char *codeset;
   wchar_t wch = L'w';
   setlocale(LC_ALL, "");
   resize_term(0, 0);
   addwstr(L"wide chars\n");
   addnwstr(&wch, 1);
   add_wch(WACS_DEGREE);
-  return 0;
+  codeset = nl_langinfo(CODESET);
+  return codeset != 0;
 }
 EOF
   IFS=:
@@ -6251,6 +6303,7 @@ echo "libgcrypt         $gcrypt"
 echo "nettle            $nettle $(echo_version $nettle $nettle_version)"
 echo "libtasn1          $tasn1"
 echo "PAM               $auth_pam"
+echo "iconv support     $iconv"
 echo "curses support    $curses"
 echo "virgl support     $virglrenderer $(echo_version $virglrenderer $virgl_version)"
 echo "curl support      $curl"
@@ -6586,6 +6639,11 @@ fi
 if test "$cocoa" = "yes" ; then
   echo "CONFIG_COCOA=y" >> $config_host_mak
 fi
+if test "$iconv" = "yes" ; then
+  echo "CONFIG_ICONV=y" >> $config_host_mak
+  echo "ICONV_CFLAGS=$iconv_cflags" >> $config_host_mak
+  echo "ICONV_LIBS=$iconv_lib" >> $config_host_mak
+fi
 if test "$curses" = "yes" ; then
   echo "CONFIG_CURSES=m" >> $config_host_mak
   echo "CURSES_CFLAGS=$curses_inc" >> $config_host_mak