auto import from //depot/cupcake/@135843
diff --git a/libc/include/features.h b/libc/include/features.h
new file mode 100644
index 0000000..343c84d
--- /dev/null
+++ b/libc/include/features.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#ifndef _FEATURES_H_
+#define _FEATURES_H_
+
+/* certain Linux-specific programs expect a <features.h> header file
+ * that defines various features macros
+ */
+
+/* we do include a number of BSD extensions */
+#define _BSD_SOURCE 1
+
+/* we do include a number of GNU extensions */
+#define _GNU_SOURCE 1
+
+/* C95 support */
+#undef __USE_ISOC95
+#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L
+# define __USE_ISOC95 1
+#endif
+
+/* C99 support */
+#undef __USE_ISOC99
+#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
+# define __USE_ISOC99 1
+#endif
+
+/* Posix support */
+#define __USE_POSIX 1
+#define __USE_POSIX2 1
+#define __USE_XPG 1
+
+#endif /* _FEATURES_H_ */