[libgomp, nvptx] Minimize lifetime of CUDA_ONE_CALL defines

This patch makes sure that the lifetimes of the CUDA_ONE_CALL macro (which is
defined twice in plugin-nvptx.c) are minimized, to make it obvious that the
definitions are used only in the lib-cuda.def include.

Build on x86_64 with nvptx accelerator and reg-tested libgomp.

2018-08-07  Tom de Vries  <tdevries@suse.de>

	* plugin/plugin-nvptx.c (struct cuda_lib_s, init_cuda_lib): Put
	CUDA_ONE_CALL defines right before the cuda-lib.def include, and the
	corresponding undefs right after.

From-SVN: r263345

libgomp/ChangeLog

+2018-08-07  Tom de Vries  <tdevries@suse.de>
+
+	* plugin/plugin-nvptx.c (struct cuda_lib_s, init_cuda_lib): Put
+	CUDA_ONE_CALL defines right before the cuda-lib.def include, and the
+	corresponding undefs right after.
+
 2018-08-04  Tom de Vries  <tdevries@suse.de>
 
 	* plugin/configfrag.ac: For --without-cuda-driver, set

libgomp/plugin/plugin-nvptx.c

@@ -52,10 +52,13 @@
 #if PLUGIN_NVPTX_DYNAMIC
 # include <dlfcn.h>
 
-# define CUDA_ONE_CALL(call) \
-  __typeof (call) *call;
 struct cuda_lib_s {
+
+# define CUDA_ONE_CALL(call)			\
+  __typeof (call) *call;
 #include "cuda-lib.def"
+# undef CUDA_ONE_CALL
+
 } cuda_lib;
 
 /* -1 if init_cuda_lib has not been called yet, false
@@ -74,18 +77,19 @@ init_cuda_lib (void)
   cuda_lib_inited = false;
   if (h == NULL)
     return false;
-# undef CUDA_ONE_CALL
+
 # define CUDA_ONE_CALL(call) CUDA_ONE_CALL_1 (call)
 # define CUDA_ONE_CALL_1(call) \
   cuda_lib.call = dlsym (h, #call);	\
   if (cuda_lib.call == NULL)		\
     return false;
 #include "cuda-lib.def"
+# undef CUDA_ONE_CALL
+# undef CUDA_ONE_CALL_1
+
   cuda_lib_inited = true;
   return true;
 }
-# undef CUDA_ONE_CALL
-# undef CUDA_ONE_CALL_1
 # define CUDA_CALL_PREFIX cuda_lib.
 #else
 # define CUDA_CALL_PREFIX