ci: Include enough Android headers to let us compile test EGL

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6112>

include/android_stub/backtrace/backtrace_constants.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _BACKTRACE_BACKTRACE_CONSTANTS_H
+#define _BACKTRACE_BACKTRACE_CONSTANTS_H
+
+// When the pid to be traced is set to this value, then trace the current
+// process. If the tid value is not BACKTRACE_NO_TID, then the specified
+// thread from the current process will be traced.
+#define BACKTRACE_CURRENT_PROCESS (-1)
+// When the tid to be traced is set to this value, then trace the specified
+// current thread of the specified pid.
+#define BACKTRACE_CURRENT_THREAD (-1)
+
+#define MAX_BACKTRACE_FRAMES 256
+
+#endif // _BACKTRACE_BACKTRACE_CONSTANTS_H