egl: Add _eglGetAPIContext.

It will return the currently bound context of the given API.

src/egl/main/eglcurrent.c

@@ -227,7 +227,18 @@ _eglIsCurrentThreadDummy(void)
 
 
 /**
- * Return the currently bound context, or NULL.
+ * Return the currently bound context of the given API, or NULL.
+ */
+PUBLIC _EGLContext *
+_eglGetAPIContext(EGLenum api)
+{
+   _EGLThreadInfo *t = _eglGetCurrentThread();
+   return t->CurrentContexts[_eglConvertApiToIndex(api)];
+}
+
+
+/**
+ * Return the currently bound context of the current API, or NULL.
  */
 _EGLContext *
 _eglGetCurrentContext(void)

src/egl/main/eglcurrent.h

@@ -72,6 +72,10 @@ extern EGLBoolean
 _eglIsCurrentThreadDummy(void);
 
 
+PUBLIC _EGLContext *
+_eglGetAPIContext(EGLenum api);
+
+
 PUBLIC _EGLContext *
 _eglGetCurrentContext(void);