threads: enable PTHREAD_{MUTEX,RWLOCK,COND}_INITIALIZER. (#397)

Author: whitequark

libc-top-half/musl/include/pthread.h

@@ -55,15 +55,9 @@ extern "C" {
 #define PTHREAD_PROCESS_SHARED 1
 
 
-#if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
 #define PTHREAD_MUTEX_INITIALIZER {{{0}}}
 #define PTHREAD_RWLOCK_INITIALIZER {{{0}}}
 #define PTHREAD_COND_INITIALIZER {{{0}}}
-#else
-#define PTHREAD_MUTEX_INITIALIZER 0
-#define PTHREAD_RWLOCK_INITIALIZER 0
-#define PTHREAD_COND_INITIALIZER 0
-#endif
 #define PTHREAD_ONCE_INIT 0