diff --git a/src/Fl_x.cxx b/src/Fl_x.cxx
index 6c1da73a4..59c442ed5 100644
--- a/src/Fl_x.cxx
+++ b/src/Fl_x.cxx
@@ -697,7 +697,7 @@ void fl_open_display(Display* d) {
 
 #if USE_XRANDR
   void *libxrandr_addr = dlopen("libXrandr.so.2", RTLD_LAZY);
-  if (!libxrandr_addr)  libxrandr_addr = dlopen("libXrandr.so", RTLD_LAZY);
+  if (!libxrandr_addr)  libxrandr_addr = Fl::system_driver()->dlopen("libXrandr.so");
   if (libxrandr_addr) {
     int error_base;
     typedef Bool (*XRRQueryExtension_type)(Display*, int*, int*);
diff --git a/src/drivers/Posix/Fl_Posix_System_Driver.cxx b/src/drivers/Posix/Fl_Posix_System_Driver.cxx
index c2576b268..6cf7bef55 100644
--- a/src/drivers/Posix/Fl_Posix_System_Driver.cxx
+++ b/src/drivers/Posix/Fl_Posix_System_Driver.cxx
@@ -47,14 +47,43 @@
 #endif /* !S_ISDIR */
 
 
+static void* double_dlopen(const char *filename1)
+{
+  void *ptr = ::dlopen(filename1, RTLD_LAZY | RTLD_GLOBAL);
+  if (!ptr) {
+    char filename2[FL_PATH_MAX];
+    sprintf(filename2, "%s.0", filename1);
+    ptr = dlopen(filename2, RTLD_LAZY | RTLD_GLOBAL);
+  }
+  return ptr;
+}
 
 
 void *Fl_Posix_System_Driver::dlopen(const char *filename)
 {
+  void *ptr = NULL;
 #if HAVE_DLSYM
-  return ::dlopen(filename, RTLD_LAZY);
-#endif
-  return NULL;
+  ptr = double_dlopen(filename);
+#  ifdef __APPLE_CC__ // allows testing on Darwin + XQuartz + fink
+  if (!ptr) {
+    char *f_dylib = strdup(filename);
+    strcpy(strrchr(f_dylib, '.'), ".dylib");
+    char path[FL_PATH_MAX];
+    sprintf(path, "/sw/lib/%s", f_dylib);
+    ptr = ::dlopen(path, RTLD_LAZY | RTLD_GLOBAL);
+    if (!ptr) {
+      sprintf(path, "/opt/sw/lib/%s", f_dylib);
+      ptr = ::dlopen(path, RTLD_LAZY | RTLD_GLOBAL);
+    }
+    if (!ptr) {
+      sprintf(path, "/opt/X11/lib/%s", f_dylib);
+      ptr = ::dlopen(path, RTLD_LAZY | RTLD_GLOBAL);
+    }
+    free(f_dylib);
+  }
+#  endif // __APPLE_CC__
+#endif // HAVE_DLSYM
+  return ptr;
 }
 
 int Fl_Posix_System_Driver::file_type(const char *filename)
diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.cxx b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
index d13562ea9..ff095f2c4 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
@@ -21,6 +21,7 @@
 #include "Fl_X11_Screen_Driver.H"
 #include "../Xlib/Fl_Font.H"
 #include "Fl_X11_Window_Driver.H"
+#include "../../src/Fl_System_Driver.H"
 #include "../Xlib/Fl_Xlib_Graphics_Driver.H"
 #include <FL/Fl.H>
 #include <FL/platform.H>
@@ -287,10 +288,7 @@ void Fl_X11_Screen_Driver::init() {
   static XRRSizes_type XRRSizes_f = NULL;
   if (!XRRSizes_f) {
     void *libxrandr_addr = dlopen("libXrandr.so.2", RTLD_LAZY);
-    if (!libxrandr_addr) libxrandr_addr = dlopen("libXrandr.so", RTLD_LAZY);
-#   ifdef __APPLE_CC__ // allows testing on Darwin + X11
-    if (!libxrandr_addr) libxrandr_addr = dlopen("/opt/X11/lib/libXrandr.dylib", RTLD_LAZY);
-#   endif
+    if (!libxrandr_addr) libxrandr_addr = Fl::system_driver()->dlopen("libXrandr.so");
     if (libxrandr_addr) XRRSizes_f = (XRRSizes_type)dlsym(libxrandr_addr, "XRRSizes");
   }
   if (XRRSizes_f) {
diff --git a/src/drivers/X11/Fl_X11_System_Driver.cxx b/src/drivers/X11/Fl_X11_System_Driver.cxx
index f406dce02..412d64667 100644
--- a/src/drivers/X11/Fl_X11_System_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_System_Driver.cxx
@@ -520,13 +520,6 @@ int Fl_X11_System_Driver::utf8locale() {
 #if HAVE_DLSYM && HAVE_DLFCN_H
 #include <dlfcn.h>   // for dlopen et al
 
-static void* fl_dlopen(const char *filename1, const char *filename2)
-{
-  void *ptr = dlopen(filename1, RTLD_LAZY | RTLD_GLOBAL);
-  if (!ptr) ptr = dlopen(filename2, RTLD_LAZY | RTLD_GLOBAL);
-  return ptr;
-}
-
 bool Fl_X11_System_Driver::probe_for_GTK(int major, int minor, void **ptr_gtk) {
   typedef void (*init_t)(int*, void*);
   *ptr_gtk = NULL;
@@ -536,18 +529,14 @@ bool Fl_X11_System_Driver::probe_for_GTK(int major, int minor, void **ptr_gtk) {
     *ptr_gtk = RTLD_DEFAULT; // Caution: NULL under linux, not-NULL under Darwin
   } else {
     // Try first with GTK3
-    *ptr_gtk     = fl_dlopen("libgtk-3.so", "libgtk-3.so.0");
+    *ptr_gtk = Fl::system_driver()->dlopen("libgtk3.0.so");
     if (*ptr_gtk) {
 #ifdef DEBUG
       puts("selected GTK-3\n");
 #endif
     } else {
       // Try then with GTK2
-#   ifdef __APPLE_CC__ // allows testing on Darwin + X11
-      *ptr_gtk     = ::dlopen("/sw/lib/libgtk-x11-2.0.dylib", RTLD_LAZY | RTLD_GLOBAL);
-#else
-      *ptr_gtk     = fl_dlopen("libgtk-x11-2.0.so", "libgtk-x11-2.0.so.0");
-#endif
+      *ptr_gtk = Fl::system_driver()->dlopen("libgtk-x11-2.0.so");
     }
     if (*ptr_gtk) {
 #ifdef DEBUG