Support ALC_EXT_thread_local_context in the router

Note that a given context's device must also support the extension to work. The
router's support simply lets a driver's capabilities through.

CMakeLists.txt

@@ -1288,6 +1288,7 @@ if(WIN32 AND ALSOFT_BUILD_ROUTER)
 
     ADD_LIBRARY(Router SHARED router/router.c router/alc.c router/al.c ${COMMON_OBJS})
     SET_PROPERTY(TARGET Router APPEND PROPERTY COMPILE_FLAGS ${EXTRA_CFLAGS})
+    SET_PROPERTY(TARGET Router APPEND PROPERTY COMPILE_DEFINITIONS AL_BUILD_LIBRARY AL_ALEXT_PROTOTYPES)
     SET_PROPERTY(TARGET OpenAL APPEND_STRING PROPERTY LINK_FLAGS ${EXTRA_LDFLAGS})
     IF(MSVC)
         SET_PROPERTY(TARGET Router APPEND_STRING PROPERTY LINK_FLAGS " /SUBSYSTEM:WINDOWS")

router/alc.c

@@ -39,6 +39,9 @@ static const struct {
     DECL(alcCaptureStop),
     DECL(alcCaptureSamples),
 
+    DECL(alcSetThreadContext),
+    DECL(alcGetThreadContext),
+
     DECL(alEnable),
     DECL(alDisable),
     DECL(alIsEnabled),
@@ -235,7 +238,8 @@ static const ALCchar alcErrInvalidEnum[] = "Invalid Enum";
 static const ALCchar alcErrInvalidValue[] = "Invalid Value";
 static const ALCchar alcErrOutOfMemory[] = "Out of Memory";
 static const ALCchar alcExtensionList[] =
-    "ALC_ENUMERATE_ALL_EXT ALC_ENUMERATION_EXT ALC_EXT_CAPTURE";
+    "ALC_ENUMERATE_ALL_EXT ALC_ENUMERATION_EXT ALC_EXT_CAPTURE "
+    "ALC_EXT_thread_local_context";
 
 static const ALCint alcMajorVersion = 1;
 static const ALCint alcMinorVersion = 1;