Add C++ guards.

include/epoxy/gl.h

@@ -37,6 +37,10 @@
 #ifndef __EPOXY_GL_H
 #define __EPOXY_GL_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(__gl_h_) || defined(__glext_h_)
 #error epoxy/gl.h must be included before (or in place of) GL/gl.h
 #else
@@ -49,4 +53,8 @@
 #include "epoxy/gl_generated.h"
 #include "epoxy/gl_generated_vtable_defines.h"
 
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
 #endif /* __EPOXY_GL_H */

include/epoxy/glx.h

@@ -35,6 +35,10 @@
 #ifndef __EPOXY_GLX_H
 #define __EPOXY_GLX_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(GLX_H) || defined(__glxext_h_)
 #error epoxy/glx.h must be included before (or in place of) GL/glx.h
 #else
@@ -48,4 +52,8 @@
 #include "epoxy/glx_generated.h"
 #include "epoxy/glx_generated_vtable_defines.h"
 
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
 #endif /* __EPOXY_GLX_H */