[httpd] Replace syscall with gettid, syscall deprecated on MacOS

configure.ac

@@ -50,16 +50,10 @@ AC_CHECK_HEADERS([sys/wait.h sys/param.h dirent.h getopt.h stdint.h], [],
 	[AC_MSG_ERROR([[Missing header required to build OwnTone]])])
 AC_CHECK_HEADERS([time.h], [],
 	[AC_MSG_ERROR([[Missing header required to build OwnTone]])])
-AC_CHECK_FUNCS_ONCE([posix_fadvise pipe2 syscall])
+AC_CHECK_FUNCS_ONCE([posix_fadvise pipe2 gettid])
 AC_CHECK_FUNCS([strptime strtok_r], [],
 	[AC_MSG_ERROR([[Missing function required to build OwnTone]])])
 
-dnl FreeBSD doesn't have SYS_gettid
-AC_CHECK_DECL([SYS_gettid],
-	[AC_DEFINE([HAVE_SYS_GETTID], 1,
-		[Define to 1 if SYS_gettid exists])],
-	[], [#include <sys/syscall.h>])
-
 dnl check for clock_gettime or replace it
 AC_SEARCH_LIBS([clock_gettime], [rt],
 	[AC_DEFINE([HAVE_CLOCK_GETTIME], 1,

src/httpd.c

@@ -34,10 +34,6 @@
 #include <stdint.h>
 #include <inttypes.h>
 
-#ifdef HAVE_SYS_GETTID
-#include <sys/syscall.h> // get thread ID
-#endif
-
 #include <event2/event.h>
 
 #include <regex.h>
@@ -884,8 +880,8 @@ request_async_cb(void *arg)
 {
   struct httpd_request *hreq = *(struct httpd_request **)arg;
 
-#if defined(HAVE_SYSCALL) && defined(HAVE_SYS_GETTID)
-  DPRINTF(E_DBG, hreq->module->logdomain, "%s request '%s' in worker thread %ld\n", hreq->module->name, hreq->uri, syscall(SYS_gettid));
+#ifdef HAVE_GETTID
+  DPRINTF(E_DBG, hreq->module->logdomain, "%s request '%s' in worker thread %d\n", hreq->module->name, hreq->uri, (int)gettid());
 #endif
 
   // Some handlers require an evbase to schedule events