linux: Move SDL_LinuxSetThreadPriority() elsewhere to fix build.

Fixes Bugzilla #4393.

configure

@@ -24182,6 +24182,7 @@ $as_echo "#define SDL_TIMER_UNIX 1" >>confdefs.h
             SOURCES="$SOURCES $srcdir/src/core/linux/SDL_evdev*.c"
         fi
         # Set up other core UNIX files
+        SOURCES="$SOURCES $srcdir/src/core/linux/SDL_threadprio.c"
         SOURCES="$SOURCES $srcdir/src/core/unix/*.c"
         ;;
     *-*-cygwin* | *-*-mingw32*)

configure.in

@@ -3553,6 +3553,7 @@ case "$host" in
             SOURCES="$SOURCES $srcdir/src/core/linux/SDL_evdev*.c"
         fi       
         # Set up other core UNIX files
+        SOURCES="$SOURCES $srcdir/src/core/linux/SDL_threadprio.c"
         SOURCES="$SOURCES $srcdir/src/core/unix/*.c"
         ;;
     *-*-cygwin* | *-*-mingw32*)

src/core/linux/SDL_dbus.c

@@ -21,13 +21,6 @@
 #include "../../SDL_internal.h"
 #include "SDL_dbus.h"
 
-#if !SDL_THREADS_DISABLED
-#include <sys/time.h>
-#include <sys/resource.h>
-#include <pthread.h>
-#include "SDL_system.h"
-#endif
-
 #if SDL_USE_LIBDBUS
 /* we never link directly to libdbus. */
 #include "SDL_loadso.h"
@@ -349,82 +342,6 @@ SDL_DBus_ScreensaverInhibit(SDL_bool inhibit)
 
     return SDL_TRUE;
 }
-
-#if !SDL_THREADS_DISABLED
-/* d-bus queries to org.freedesktop.RealtimeKit1. */
-#define RTKIT_DBUS_NODE "org.freedesktop.RealtimeKit1"
-#define RTKIT_DBUS_PATH "/org/freedesktop/RealtimeKit1"
-#define RTKIT_DBUS_INTERFACE "org.freedesktop.RealtimeKit1"
-
-static pthread_once_t rtkit_initialize_once = PTHREAD_ONCE_INIT;
-static Sint32 rtkit_min_nice_level = -20;
-
-static void
-rtkit_initialize()
-{
-    SDL_DBusContext *dbus = SDL_DBus_GetContext();
-
-    /* Try getting minimum nice level: this is often greater than PRIO_MIN (-20). */
-    if (!dbus || !SDL_DBus_QueryPropertyOnConnection(dbus->system_conn, RTKIT_DBUS_NODE, RTKIT_DBUS_PATH, RTKIT_DBUS_INTERFACE, "MinNiceLevel",
-                                            DBUS_TYPE_INT32, &rtkit_min_nice_level)) {
-        rtkit_min_nice_level = -20;
-    }
-}
-
-static SDL_bool
-rtkit_setpriority(pid_t thread, int nice_level)
-{
-    Uint64 ui64 = (Uint64)thread;
-    Sint32 si32 = (Sint32)nice_level;
-    SDL_DBusContext *dbus = SDL_DBus_GetContext();
-
-    pthread_once(&rtkit_initialize_once, rtkit_initialize);
-
-    if (si32 < rtkit_min_nice_level)
-        si32 = rtkit_min_nice_level;
-
-    if (!dbus || !SDL_DBus_CallMethodOnConnection(dbus->system_conn,
-            RTKIT_DBUS_NODE, RTKIT_DBUS_PATH, RTKIT_DBUS_INTERFACE, "MakeThreadHighPriority",
-            DBUS_TYPE_UINT64, &ui64, DBUS_TYPE_INT32, &si32, DBUS_TYPE_INVALID,
-            DBUS_TYPE_INVALID)) {
-        return SDL_FALSE;
-    }
-    return SDL_TRUE;
-}
 #endif
 
-#endif
-
-/* this is a public symbol, so it has to exist even if threads are disabled. */
-int
-SDL_LinuxSetThreadPriority(Sint64 threadID, int priority)
-{
-#if SDL_THREADS_DISABLED
-    return SDL_Unsupported();
-#else
-    if (setpriority(PRIO_PROCESS, (id_t)threadID, priority) == 0) {
-        return 0;
-    }
-
-#if SDL_USE_LIBDBUS
-    /* Note that this fails if you're trying to set high priority
-       and you don't have root permission. BUT DON'T RUN AS ROOT!
-
-       You can grant the ability to increase thread priority by
-       running the following command on your application binary:
-          sudo setcap 'cap_sys_nice=eip' <application>
-
-       Let's try setting priority with RealtimeKit...
-
-       README and sample code at: http://git.0pointer.net/rtkit.git
-    */
-    if (rtkit_setpriority((pid_t)threadID, priority)) {
-        return 0;
-    }
-#endif
-
-    return SDL_SetError("setpriority() failed");
-#endif
-}
-
 /* vi: set ts=4 sw=4 expandtab: */

src/thread/pthread/SDL_systhread.c

@@ -20,6 +20,7 @@
 */
 
 #include "../../SDL_internal.h"
+#include "SDL_system.h"
 
 #include <pthread.h>