LC_CTYPE specific hints to Xft selection

This is not as smart as libpango and similar but should instruct Xft
sufficiently to select a Sans compatible font which actually brings the
required codeset.

Closes ice-wm/icewm#149

src/fontmacro.h

@@ -43,12 +43,17 @@
 
 #endif
 
+// Prefer DejaVu but fallback to some other Sans provider if needed,
+// influenced by :lang= later in yfontxft.cc.
+
 #define FQUOT(x) #x
 #define FSIZE(x) ":size=" FQUOT(x)
-#define FSANS   "DejaVu Sans" FSIZE(12)
-#define FBOLD   FSANS ":bold"
-#define FSMAL   "DejaVu Sans" FSIZE(10) ":bold"
-#define FMONO   "DejaVu Sans Mono:monospace" FSIZE(12)
-#define FMONB   FMONO ":bold"
+#define FSANSTOK "DejaVu Sans,Sans"
+#define FBOLDTOK ":bold"
+#define FSANS   FSANSTOK FSIZE(12)
+#define FBOLD   FSANS FBOLDTOK
+#define FSMAL   FSANSTOK FSIZE(10) FBOLDTOK
+#define FMONO   "DejaVu Sans Mono,Sans Mono:monospace" FSIZE(12)
+#define FMONB   FMONO FBOLDTOK
 
 #endif

src/yfontxft.cc

@@ -109,6 +109,16 @@ YXftFont::YXftFont(mstring name, bool use_xlfd):
             if (use_xlfd) {
                 font = XftFontOpenXlfd(xapp->display(), xapp->screen(), fname);
             } else {
+
+                if (fname.find(":lang=") < 0)
+                {
+                    auto lclocale = mstring(YLocale::getLcType()).lower();
+                    if (lclocale.length() >= 5 && lclocale[2] == '_') {
+                        fname = fname + ":lang=" + lclocale.substring(0,2) + "-"
+                                + lclocale.substring(3,2);
+                    }
+                }
+
                 font = XftFontOpenName(xapp->display(), xapp->screen(), fname);
             }
             if (font) {

src/ylocale.cc

@@ -322,6 +322,15 @@ char* YLocale::narrowString(const wchar_t* uStr, size_t uLen, size_t& lLen) {
     return dest;
 }
 
+const char *YLocale::getLcType()
+{
+    auto cur_lctype = setlocale(LC_CTYPE, NULL);
+    if (cur_lctype == NULL) {
+        return "C";
+    }
+    return cur_lctype;
+}
+
 const char *YLocale::getLocaleName() {
 #ifdef CONFIG_I18N
     return instance->converter->localeName();

src/ylocale.h

@@ -27,6 +27,7 @@ class YLocale {
     static wchar_t* wideCharString(const char* str, size_t len, size_t& out);
 #endif
     static char* narrowString(const wchar_t* uStr, size_t uLen, size_t& lLen);
+    static const char* getLcType();
 
 private:
     class YConverter* converter;