Split future symbols into a new file and added one we need to fix our button cell renderer on 3.20.

unix/CMakeLists.txt

@@ -24,6 +24,7 @@ list(APPEND _LIBUI_SOURCES
 	unix/entry.c
 	unix/fontbutton.c
 	unix/form.c
+	unix/future.c
 	unix/graphemes.c
 	unix/grid.c
 	unix/group.c

unix/drawtext.c

@@ -273,25 +273,6 @@ static void addAttr(uiDrawTextLayout *layout, PangoAttribute *attr, int startCha
 	// pango_attr_list_insert() takes attr; we don't free it
 }
 
-// these attributes are only supported on 1.38 and higher; we need to support 1.36
-// use dynamic linking to make them work at least on newer systems
-static PangoAttribute *(*newFGAlphaAttr)(guint16 alpha) = NULL;
-static gboolean tried138 = FALSE;
-
-// note that we treat any error as "the 1.38 symbols aren't there" (and don't care if dlclose() failed)
-static void try138(void)
-{
-	void *handle;
-
-	tried138 = TRUE;
-	// dlsym() walks the dependency chain, so opening the current process should be sufficient
-	handle = dlopen(NULL, RTLD_LAZY);
-	if (handle == NULL)
-		return;
-	*((void **) (&newFGAlphaAttr)) = dlsym(handle, "pango_attr_foreground_alpha_new");
-	dlclose(handle);
-}
-
 void uiDrawTextLayoutSetColor(uiDrawTextLayout *layout, int startChar, int endChar, double r, double g, double b, double a)
 {
 	PangoAttribute *attr;
@@ -305,11 +286,8 @@ void uiDrawTextLayoutSetColor(uiDrawTextLayout *layout, int startChar, int endCh
 	attr = pango_attr_foreground_new(rr, gg, bb);
 	addAttr(layout, attr, startChar, endChar);
 
-	if (!tried138)
-		try138();
 	// TODO what if aa == 0?
-	if (newFGAlphaAttr != NULL) {
-		attr = (*newFGAlphaAttr)(aa);
+	attr = FUTURE_pango_attr_foreground_alpha_new(aa);
+	if (attr != NULL)
 		addAttr(layout, attr, startChar, endChar);
-	}
 }

unix/future.c

@@ -0,0 +1,42 @@
+// 29 june 2016
+#include "uipriv_unix.h"
+
+// functions FROM THE FUTURE!
+// in some cases, because being held back by LTS releases sucks :/
+// in others, because parts of GTK+ being unstable until recently also sucks :/
+
+// added in pango 1.38; we need 1.36
+static PangoAttribute *(*newFGAlphaAttr)(guint16 alpha) = NULL;
+
+// added in GTK+ 3.20; we need 3.10
+static void (*gwpIterSetObjectName)(GtkWidgetPath *path, gint pos, const char *name) = NULL;
+
+// note that we treat any error as "the symbols aren't there" (and don't care if dlclose() failed)
+void loadFutures(void)
+{
+	void *handle;
+
+	// dlsym() walks the dependency chain, so opening the current process should be sufficient
+	handle = dlopen(NULL, RTLD_LAZY);
+	if (handle == NULL)
+		return;
+#define GET(var, fn) *((void **) (&var)) = dlsym(handle, #fn)
+	GET(newFGAlphaAttr, pango_attr_foreground_alpha_new);
+	GET(gwpIterSetObjectName, gtk_widget_path_iter_set_object_name);
+	dlclose(handle);
+}
+
+PangoAttribute *FUTURE_pango_attr_foreground_alpha_new(guint16 alpha)
+{
+	if (newFGAlphaAttr == NULL)
+		return NULL;
+	return (*newFGAlphaAttr)(alpha);
+}
+
+gboolean FUTURE_gtk_widget_path_iter_set_object_name(GtkWidgetPath *path, gint pos, const char *name)
+{
+	if (gwpIterSetObjectName == NULL)
+		return FALSE;
+	(*gwpIterSetObjectName)(path, pos, name);
+	return TRUE;
+}

unix/main.c

@@ -15,6 +15,7 @@ const char *uiInit(uiInitOptions *o)
 		return msg;
 	}
 	initAlloc();
+	loadFutures();
 	return NULL;
 }
 

unix/uipriv_unix.h

@@ -57,3 +57,8 @@ extern cairo_surface_t *imageAppropriateSurface(uiImage *i, GtkWidget *w);
 
 // cellrendererbutton.c
 extern GtkCellRenderer *newCellRendererButton(void);
+
+// future.c
+extern void loadFutures(void);
+extern PangoAttribute *FUTURE_pango_attr_foreground_alpha_new(guint16 alpha);
+extern gboolean FUTURE_gtk_widget_path_iter_set_object_name(GtkWidgetPath *path, gint pos, const char *name);