thread/Name: disable pthread_setname_np() on NetBSD

NetBSD's pthread_setname_np() prototype is incompatible with the rest
of the world, and it requires to pass the string argument as a
non-const pointer.  Instead of working around this misdesign, I hereby
disable the feature on NetBSD.

NEWS

@@ -5,6 +5,7 @@ ver 0.19.8 (not yet released)
   - dsdiff, dsf: allow ID3 tags larger than 4 kB
   - ffmpeg: support interleaved floating point
 * fix clang 3.6 warnings
+* fix build failure on NetBSD
 
 ver 0.19.7 (2014/12/17)
 * input

src/thread/Name.hxx

@@ -20,7 +20,7 @@
 #ifndef MPD_THREAD_NAME_HXX
 #define MPD_THREAD_NAME_HXX
 
-#ifdef HAVE_PTHREAD_SETNAME_NP
+#if defined(HAVE_PTHREAD_SETNAME_NP) && !defined(__NetBSD__)
 #  define HAVE_THREAD_NAME
 #  include <pthread.h>
 #  include <stdio.h>
@@ -34,7 +34,11 @@
 static inline void
 SetThreadName(const char *name)
 {
-#ifdef HAVE_PTHREAD_SETNAME_NP
+#if defined(HAVE_PTHREAD_SETNAME_NP) && !defined(__NetBSD__)
+	/* not using pthread_setname_np() on NetBSD because it
+	   requires a non-const pointer argument, which we don't have
+	   here */
+
 #ifdef __APPLE__
 	pthread_setname_np(name);
 #else