Fix GHOST crash on X11 with recent DPI changes on some systems.

intern/ghost/intern/GHOST_WindowX11.cpp

@@ -1683,6 +1683,7 @@ getDPIHint()
 {
 	/* Try to read DPI setting set using xrdb */
 	char* resMan = XResourceManagerString(m_display);
+	if (resMan) {
 		XrmDatabase xrdb = XrmGetStringDatabase(resMan);
 		if (xrdb) {
 			char* type = NULL;
@@ -1695,6 +1696,7 @@ getDPIHint()
 				}
 			}
 		}
+	}
 
 	/* Fallback to calculating DPI using X reported DPI, set using xrandr --dpi */
 	XWindowAttributes attr;