Implement enif_tsd_* stubs

Makefile

@@ -9,7 +9,7 @@ CC ?= gcc
 CFLAGS ?= -MMD -std=gnu99 -Wall -Wextra -ggdb -fms-extensions -rdynamic -Wno-missing-field-initializers
 CFLAGS := $(CFLAGS) -I$(ERTS_INCLUDE_DIR) $(DEFINES)
 PARSE_CFLAGS := $(CFLAGS) -Wno-unused-variable -Wno-unused-parameter -Wno-sign-compare
-LDFLAGS ?= -ldl
+LDFLAGS ?= -ldl -pthread
 RAGEL ?= ragel
 RAGELFLAGS ?= -G2
 PROVEFLAGS ?=

nif_stubs.c

@@ -1,6 +1,7 @@
 
 #include <assert.h>
 #include <ctype.h>
+#include <pthread.h>
 #include <stdarg.h>
 #include <string.h>
 
@@ -1033,6 +1034,30 @@ int enif_get_string(ErlNifEnv *UNUSED, term t, char *buf, unsigned size,
 }
 
 
+int enif_tsd_key_create(char *UNUSED, ErlNifTSDKey *key)
+{
+    return pthread_key_create((pthread_key_t *)key, NULL);
+}
+
+
+void enif_tsd_key_destroy(ErlNifTSDKey key)
+{
+    assert(0 == pthread_key_delete(key));
+}
+
+
+void enif_tsd_set(ErlNifTSDKey key, void *data)
+{
+    assert(0 == pthread_setspecific(key, data));
+}
+
+
+void *enif_tsd_get(ErlNifTSDKey key)
+{
+    return pthread_getspecific(key);
+}
+
+
 /*
  * FUNCTIONS WHOSE IMPLEMENTATION IS PATHOLOGICAL
  */