Avoid conflicts with multiple versions of udev by first trying the library that is linked with the executable, if any, and then picking the one that is in the build environment.

This fixes joystick detection for applications using the Steam Linux Runtime

configure

@@ -21578,6 +21578,16 @@ fi
 
 $as_echo "#define HAVE_LIBUDEV_H 1" >>confdefs.h
 
+
+            udev_lib=`find_lib "libudev.so.*" "" | sed 's/.*\/\(.*\)/\1/; q'`
+            if test x$udev_lib != x; then
+                echo "-- dynamic udev -> $udev_lib"
+
+cat >>confdefs.h <<_ACEOF
+#define SDL_UDEV_DYNAMIC "$udev_lib"
+_ACEOF
+
+            fi
         fi
     fi
 }

configure.in

@@ -2231,6 +2231,12 @@ AC_HELP_STRING([--enable-libudev], [enable libudev support [[default=yes]]]),
                         have_libudev_h_hdr=no)
         if test x$have_libudev_h_hdr = xyes; then
             AC_DEFINE(HAVE_LIBUDEV_H, 1, [ ])
+
+            udev_lib=[`find_lib "libudev.so.*" "" | sed 's/.*\/\(.*\)/\1/; q'`]
+            if test x$udev_lib != x; then
+                echo "-- dynamic udev -> $udev_lib"
+                AC_DEFINE_UNQUOTED(SDL_UDEV_DYNAMIC, "$udev_lib", [ ])
+            fi
         fi
     fi
 }

include/SDL_config.h.in

@@ -360,4 +360,7 @@
 /* Enable ime support */
 #undef SDL_USE_IME
 
+/* Enable dynamic udev support */
+#undef SDL_UDEV_DYNAMIC
+
 #endif /* SDL_config_h_ */

src/core/linux/SDL_dbus.c

@@ -237,3 +237,5 @@ SDL_DBus_ScreensaverInhibit(SDL_bool inhibit)
     }
 }
 #endif
+
+/* vi: set ts=4 sw=4 expandtab: */

src/core/linux/SDL_ibus.c

@@ -680,3 +680,5 @@ SDL_IBus_PumpEvents(void)
 }
 
 #endif
+
+/* vi: set ts=4 sw=4 expandtab: */

src/core/linux/SDL_ime.c

@@ -136,3 +136,5 @@ SDL_IME_PumpEvents()
     if (SDL_IME_PumpEvents_Real)
         SDL_IME_PumpEvents_Real();
 }
+
+/* vi: set ts=4 sw=4 expandtab: */

src/core/linux/SDL_udev.c

@@ -33,7 +33,14 @@
 
 #include "SDL.h"
 
-static const char* SDL_UDEV_LIBS[] = { "libudev.so.1", "libudev.so.0" };
+static const char *SDL_UDEV_LIBS[] = {
+#ifdef SDL_UDEV_DYNAMIC
+	SDL_UDEV_DYNAMIC
+#else
+	"libudev.so.1",
+	"libudev.so.0"
+#endif
+};
 
 #define _THIS SDL_UDEV_PrivateData *_this
 static _THIS = NULL;
@@ -253,6 +260,10 @@ SDL_UDEV_LoadLibrary(void)
         return SDL_SetError("UDEV not initialized");
     }
  
+    /* See if there is a udev library already loaded */
+    if (SDL_UDEV_load_syms() == 0) {
+        return 0;
+    }
 
     if (_this->udev_handle == NULL) {
         for( i = 0 ; i < SDL_arraysize(SDL_UDEV_LIBS); i++) {
@@ -536,3 +547,5 @@ SDL_UDEV_DelCallback(SDL_UDEV_Callback cb)
 
 
 #endif /* SDL_USE_LIBUDEV */
+
+/* vi: set ts=4 sw=4 expandtab: */