mesa: Rename GLX_USE_TLS to USE_ELF_TLS.

These days it is not GLX only and it does not work with all TLS
implementations.

Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>

src/glx/glxclient.h

@@ -660,7 +660,7 @@ extern int __glXDebug;
 
 extern void __glXSetCurrentContext(struct glx_context * c);
 
-# if defined( GLX_USE_TLS )
+# if defined( USE_ELF_TLS )
 
 extern __thread void *__glX_tls_Context
    __attribute__ ((tls_model("initial-exec")));
@@ -671,7 +671,7 @@ extern __thread void *__glX_tls_Context
 
 extern struct glx_context *__glXGetCurrentContext(void);
 
-# endif /* defined( GLX_USE_TLS ) */
+# endif /* defined( USE_ELF_TLS ) */
 
 extern void __glXSetCurrentContextNull(void);
 

src/glx/glxcurrent.c

@@ -67,7 +67,7 @@ struct glx_context dummyContext = {
 
 _X_HIDDEN pthread_mutex_t __glXmutex = PTHREAD_MUTEX_INITIALIZER;
 
-# if defined( GLX_USE_TLS )
+# if defined( USE_ELF_TLS )
 
 /**
  * Per-thread GLX context pointer.
@@ -132,7 +132,7 @@ __glXGetCurrentContext(void)
    return (v == NULL) ? &dummyContext : (struct glx_context *) v;
 }
 
-# endif /* defined( GLX_USE_TLS ) */
+# endif /* defined( USE_ELF_TLS ) */
 
 
 _X_HIDDEN void

src/glx/tests/fake_glx_screen.cpp

@@ -102,7 +102,7 @@ struct glx_context dummyContext = {
 };
 __thread void *__glX_tls_Context = &dummyContext;
 
-#if !defined(GLX_USE_TLS)
+#if !defined(USE_ELF_TLS)
 extern "C" struct glx_context *
 __glXGetCurrentContext()
 {