glx: Don't enclose includes inside `extern "C" { }`.

Ran `make check` inside src/glx to verify everything compiles and links
correctly.

https://bugs.freedesktop.org/show_bug.cgi?id=95158

Reviewed-by: Brian Paul <brianp@vmware.com>

src/glx/dri2_priv.h

@@ -30,6 +30,10 @@
  *   Kristian Høgsberg (krh@redhat.com)
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct dri2_screen {
    struct glx_screen base;
 
@@ -74,3 +78,7 @@ _X_HIDDEN int
 dri2_interop_export_object(struct glx_context *ctx,
                            const mesa_glinterop_export_in *in,
                            mesa_glinterop_export_out *out);
+
+#ifdef __cplusplus
+}
+#endif

src/glx/glx_error.h

@@ -31,9 +31,17 @@
 #include <X11/Xlib.h>
 #include <xcb/xcb.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void __glXSendError(Display * dpy, int_fast8_t errorCode,
 		    uint_fast32_t resourceID, uint_fast16_t minorCode,
 		    bool coreX11error);
 
 _X_HIDDEN void __glXSendErrorForXcb(Display * dpy,
 				    const xcb_generic_error_t *err);
+
+#ifdef __cplusplus
+}
+#endif

src/glx/glxclient.h

@@ -57,6 +57,11 @@
 #include "glxextensions.h"
 
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 #define GLX_MAJOR_VERSION 1       /* current version numbers */
 #define GLX_MINOR_VERSION 4
 
@@ -824,4 +829,8 @@ indirect_create_context_attribs(struct glx_screen *base,
                                 const uint32_t *attribs,
                                 unsigned *error);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* !__GLX_client_h__ */

src/glx/glxextensions.h

@@ -31,6 +31,10 @@
 #ifndef GLX_GLXEXTENSIONS_H
 #define GLX_GLXEXTENSIONS_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 enum
 {
    ARB_create_context_bit = 0,
@@ -303,4 +307,8 @@ typedef void (*PFNGLXDISABLEEXTENSIONPROC) (const char *name);
 # endif /* __GNUC__ */
 #endif /* GLX_NO_STATIC_EXTENSION_FUNCTIONS */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GLX_GLXEXTENSIONS_H */

src/glx/tests/clientinfo_unittest.cpp

@@ -23,9 +23,7 @@
 #include <gtest/gtest.h>
 #include <string.h>
 
-extern "C" {
 #include "glxclient.h"
-}
 
 #include <xcb/glx.h>
 

src/glx/tests/create_context_unittest.cpp

@@ -23,10 +23,8 @@
 #include <gtest/gtest.h>
 #include <string.h>
 
-extern "C" {
 #include "glxclient.h"
 #include "glx_error.h"
-}
 
 #include <xcb/glx.h>
 #include "mock_xdisplay.h"

src/glx/tests/fake_glx_screen.h

@@ -20,9 +20,7 @@
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  */
-extern "C" {
 #include "glxclient.h"
-};
 
 class fake_glx_screen : public glx_screen {
 public:

src/glx/tests/query_renderer_implementation_unittest.cpp

@@ -26,13 +26,11 @@
 
 #if defined(GLX_DIRECT_RENDERING) && !defined(GLX_USE_APPLEGL)
 
-extern "C" {
 #include "glxclient.h"
 #include "glx_error.h"
 #include "dri2.h"
 #include "dri_interface.h"
 #include "dri2_priv.h"
-}
 
 struct attribute_test_vector {
    const char *glx_string;

src/glx/tests/query_renderer_unittest.cpp

@@ -24,10 +24,8 @@
 #include <signal.h>
 #include <setjmp.h>
 
-extern "C" {
 #include "glxclient.h"
 #include "glx_error.h"
-}
 
 extern bool GetGLXScreenConfigs_called;
 extern struct glx_screen *psc;