semaphores: fix missed wakes from ABA bug in waiter count logic

[musl] / include / strings.h

diff --git a/include/strings.h b/include/strings.h
index 2b7e086..b7a5ea0 100644 (file)
--- a/include/strings.h
+++ b/include/strings.h
@@ -5,6 +5,7 @@
 extern "C" {
 #endif
 
+#include <features.h>
 
 #define __NEED_size_t
 #define __NEED_locale_t
@@ -20,7 +21,11 @@ char *index (const char *, int);
 char *rindex (const char *, int);
 #endif
 
+#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)  || defined(_BSD_SOURCE)
 int ffs (int);
+int ffsl (long);
+int ffsll (long long);
+#endif
 
 int strcasecmp (const char *, const char *);
 int strncasecmp (const char *, const char *, size_t);