emulator opengl: add GLESv2 support to driver + renderer

Added GLESv2 library to system.
Made fixes to the host libOpenGLRender to
compile and support GLESv2 (defined WITH_GLES2).
Other fixes required to make GLESv2 to work.

Change-Id: I9eb198e6092e7fa3550342c50929dd1714282cb3

tools/emulator/opengl/system/OpenglSystemCommon/QemuPipeStream.cpp

@@ -117,7 +117,7 @@ const unsigned char *QemuPipeStream::readFully(void *buf, size_t len)
     //DBG(">> QemuPipeStream::readFully %d\n", len);
     if (!valid()) return NULL;
     if (!buf) {
-        ERR("QemuPipeStream::readFully failed, buf=NULL");
+        ERR("QemuPipeStream::readFully failed, buf=NULL, len %d", len);
         return NULL;  // do not allow NULL buf in that implementation
     }
     size_t res = len;