qt: fix unicode character display on osx when building with 10.7 sdk

Conflicts:
	src/qt/bitcoin.cpp

Rebased-From: 292cc072

doc/release-notes.md

@@ -61,6 +61,7 @@ Wallet:
 GUI:
 - fix 'opens in testnet mode when presented with a BIP-72 link with no fallback'
 - AvailableCoins: acquire cs_main mutex
+- Fix unicode character display on MacOSX
 
 Miscellaneous:
 - key.cpp: fail with a friendlier message on missing ssl EC support

src/qt/bitcoin.cpp

@@ -475,6 +475,9 @@ int main(int argc, char *argv[])
 #endif
 
     Q_INIT_RESOURCE(bitcoin);
+
+    GUIUtil::SubstituteFonts();
+
     BitcoinApplication app(argc, argv);
 #if QT_VERSION > 0x050100
     // Generate high-dpi pixmaps

src/qt/guiutil.cpp

@@ -61,6 +61,13 @@
 static boost::filesystem::detail::utf8_codecvt_facet utf8;
 #endif
 
+#if defined(Q_OS_MAC)
+extern double NSAppKitVersionNumber;
+#if !defined(NSAppKitVersionNumber10_9)
+#define NSAppKitVersionNumber10_9 1265
+#endif
+#endif
+
 namespace GUIUtil {
 
 QString dateTimeStr(const QDateTime &date)
@@ -372,6 +379,26 @@ ToolTipToRichTextFilter::ToolTipToRichTextFilter(int size_threshold, QObject *pa
 
 }
 
+void SubstituteFonts()
+{
+#if defined(Q_OS_MAC)
+// Background:
+// OSX's default font changed in 10.9 and QT is unable to find it with its
+// usual fallback methods when building against the 10.7 sdk or lower.
+// The 10.8 SDK added a function to let it find the correct fallback font.
+// If this fallback is not properly loaded, some characters may fail to
+// render correctly.
+//
+// Solution: If building with the 10.7 SDK or lower and the user's platform
+// is 10.9 or higher at runtime, substitute the correct font. This needs to
+// happen before the QApplication is created.
+#if defined(MAC_OS_X_VERSION_MAX_ALLOWED) && MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_8
+    if (floor(NSAppKitVersionNumber) >= NSAppKitVersionNumber10_9)
+        QFont::insertSubstitution(".Lucida Grande UI", "Lucida Grande");
+#endif
+#endif
+}
+
 bool ToolTipToRichTextFilter::eventFilter(QObject *obj, QEvent *evt)
 {
     if(evt->type() == QEvent::ToolTipChange)

src/qt/guiutil.h

@@ -106,6 +106,10 @@ namespace GUIUtil
       representation if needed. This assures that Qt can word-wrap long tooltip messages.
       Tooltips longer than the provided size threshold (in characters) are wrapped.
      */
+
+    // Replace invalid default fonts with known good ones
+    void SubstituteFonts();
+
     class ToolTipToRichTextFilter : public QObject
     {
         Q_OBJECT