add some missing prototypes for nonstandard functions (strsep, clearenv)

include/stdlib.h

@@ -124,6 +124,7 @@ void lcong48 (unsigned short [7]);
 char *mktemp (char *);
 void *valloc (size_t);
 void *memalign(size_t, size_t);
+int clearenv(void);
 #endif
 
 

include/string.h

@@ -73,6 +73,7 @@ int strcasecmp (const char *, const char *);
 int strncasecmp (const char *, const char *, size_t);
 char *strchrnul(const char *, int);
 char *strcasestr(const char *, const char *);
+char *strsep(char **, char *);
 #endif
 
 #ifdef __cplusplus