Rename m-mutex header into m-thread

as it is not just about mutex but about thread functions
just like the header pthread or thread.h

tests/test-mcmempool.c

@@ -24,7 +24,7 @@
 */
 
 #include "m-c-mempool.h"
-#include "m-mutex.h"
+#include "m-thread.h"
 
 C_MEMPOOL_DEF(lf_mempool, int)
 

tests/test-mgenint.c

@@ -21,7 +21,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 #include <stdio.h>
-#include "m-mutex.h"
+#include "m-thread.h"
 #include "m-atomic.h"
 
 #include "m-genint.h"

tests/test-mishared.c

@@ -25,7 +25,7 @@
 
 #include "m-i-shared.h"
 
-#include "m-mutex.h"
+#include "m-thread.h"
 #include "coverage.h"
 
 typedef struct ishared_s {

tests/test-mmutex.c

@@ -22,7 +22,7 @@
 */
 #include <stdio.h>
 
-#include "m-mutex.h"
+#include "m-thread.h"
 
 M_LOCK_DECL(global_lock);
 unsigned long long n = 0;

tests/test-msnapshot.c

@@ -23,7 +23,7 @@
 #include "test-obj.h"
 
 #include "m-snapshot.h"
-#include "m-mutex.h"
+#include "m-thread.h"
 
 #include "coverage.h"