system/FileDescriptor: make inotify_init1() mandatory on Linux

configure.ac

@@ -587,9 +587,7 @@ if test x$enable_qobuz != xno || test x$enable_soundcloud != xno || test x$enabl
 fi
 
 dnl --------------------------------- inotify ---------------------------------
-AC_CHECK_FUNCS(inotify_init inotify_init1)
-
-if test x$ac_cv_func_inotify_init = xno; then
+if test x$host_is_linux = xno; then
 	enable_inotify=no
 fi
 

src/system/FileDescriptor.cxx

@@ -45,7 +45,7 @@
 #include <sys/signalfd.h>
 #endif
 
-#ifdef HAVE_INOTIFY_INIT
+#ifdef __linux__
 #include <sys/inotify.h>
 #endif
 
@@ -248,23 +248,15 @@ FileDescriptor::CreateSignalFD(const sigset_t *mask) noexcept
 
 #endif
 
-#ifdef HAVE_INOTIFY_INIT
+#ifdef __linux__
 
 bool
 FileDescriptor::CreateInotify() noexcept
 {
-#ifdef HAVE_INOTIFY_INIT1
 	int new_fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
-#else
-	int new_fd = inotify_init();
-#endif
 	if (new_fd < 0)
 		return false;
 
-#ifndef HAVE_INOTIFY_INIT1
-	SetNonBlocking();
-#endif
-
 	fd = new_fd;
 	return true;
 }

src/system/FileDescriptor.hxx

@@ -189,7 +189,7 @@ public:
 	bool CreateSignalFD(const sigset_t *mask) noexcept;
 #endif
 
-#ifdef HAVE_INOTIFY_INIT
+#ifdef __linux__
 	bool CreateInotify() noexcept;
 #endif