Remove redundant #ifdef HAVE_THREAD, the file is only compiled

if that condition holds anyway.

Originally committed as revision 7029 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/os2thread.c

@@ -25,8 +25,6 @@
 #include "avcodec.h"
 #include "common.h"
 
-#ifdef HAVE_THREADS
-
 #define INCL_DOS
 #define INCL_DOSERRORS
 #define INCL_DOSDEVIOCTL
@@ -147,4 +145,3 @@ fail:
     avcodec_thread_free(s);
     return -1;
 }
-#endif