diff --git a/libc/include/sys/cdefs.h b/libc/include/sys/cdefs.h
index ca81cb6..937abe0 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -177,6 +177,8 @@
 #define	__unused	/* delete */
 #endif
 
+#define __pure2 __attribute__((__const__)) /* Android-added: used by FreeBSD libm */
+
 #if __GNUC_PREREQ__(3, 1)
 #define	__used		__attribute__((__used__))
 #else
@@ -313,6 +315,12 @@
 #define __purefunc
 #endif
 
+#if __GNUC_PREREQ__(3, 1)
+#define __always_inline __attribute__((__always_inline__))
+#else
+#define __always_inline
+#endif
+
 /*
  * Macros for manipulating "link sets".  Link sets are arrays of pointers
  * to objects, which are gathered up by the linker.
@@ -510,4 +518,11 @@
 #define __BIONIC_FORTIFY_UNKNOWN_SIZE ((size_t) -1)
 #endif
 
+/* Android-added: for FreeBSD's libm. */
+#define __weak_reference(sym,alias) \
+    __asm__(".weak " #alias); \
+    __asm__(".equ "  #alias ", " #sym)
+#define __strong_reference(sym,aliassym) \
+    extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym)))
+
 #endif /* !_SYS_CDEFS_H_ */