diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 4cb288d..308007a 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -76,10 +76,10 @@
 
 extern int posix_memalign(void **memptr, size_t alignment, size_t size);
 
-extern double atof(const char*);
+_BIONIC_NOT_BEFORE_21(extern double atof(const char*);)
 
 extern double strtod(const char*, char**) __LIBC_ABI_PUBLIC__;
-extern float strtof(const char*, char**) __LIBC_ABI_PUBLIC__;
+_BIONIC_NOT_BEFORE_21(extern float strtof(const char*, char**) __LIBC_ABI_PUBLIC__;)
 extern long double strtold(const char*, char**) __LIBC_ABI_PUBLIC__;
 
 extern long double strtold_l(const char *, char **, locale_t) __LIBC_ABI_PUBLIC__;
@@ -90,9 +90,9 @@
 extern long atol(const char*) __purefunc;
 extern long long atoll(const char*) __purefunc;
 
-extern int abs(int) __pure2;
-extern long labs(long) __pure2;
-extern long long llabs(long long) __pure2;
+_BIONIC_NOT_BEFORE_21(extern int abs(int) __pure2;)
+_BIONIC_NOT_BEFORE_21(extern long labs(long) __pure2;)
+_BIONIC_NOT_BEFORE_21(extern long long llabs(long long) __pure2;)
 
 extern char * realpath(const char *path, char *resolved);
 extern int system(const char * string);
@@ -109,9 +109,9 @@
 
 #define RAND_MAX 0x7fffffff
 
-int rand(void);
+_BIONIC_NOT_BEFORE_21(int rand(void);)
 int rand_r(unsigned int*);
-void srand(unsigned int);
+_BIONIC_NOT_BEFORE_21(void srand(unsigned int);)
 
 double drand48(void);
 double erand48(unsigned short[3]);
@@ -124,12 +124,12 @@
 void srand48(long);
 
 char* initstate(unsigned int, char*, size_t);
-long random(void);
+_BIONIC_NOT_BEFORE_21(long random(void);)
 char* setstate(char*);
-void srandom(unsigned int);
+_BIONIC_NOT_BEFORE_21(void srandom(unsigned int);)
 
 int getpt(void);
-int grantpt(int);
+_BIONIC_NOT_BEFORE_21(int grantpt(int);)
 int posix_openpt(int);
 char* ptsname(int);
 int ptsname_r(int, char*, size_t);
@@ -172,6 +172,10 @@
 extern size_t __ctype_get_mb_cur_max(void);
 #define MB_CUR_MAX __ctype_get_mb_cur_max()
 
+#if __ANDROID_API__ < 21
+#include <android/legacy_stdlib_inlines.h>
+#endif
+
 __END_DECLS
 
 #endif /* _STDLIB_H */