restore direct libm dependency (fixes #222)

meson.build

@@ -39,6 +39,7 @@ wlroots        = dependency('wlroots', version: '>= 0.15.0', fallback: ['wlroots
 wayland_protos = dependency('wayland-protocols', version: '>=1.14')
 wayland_server = dependency('wayland-server')
 xkbcommon      = dependency('xkbcommon')
+math           = dependency('m')
 
 wl_protocol_dir = wayland_protos.get_pkgconfig_variable('pkgdatadir')
 wayland_scanner = find_program('wayland-scanner')
@@ -153,6 +154,7 @@ executable(
     wayland_server,
     wlroots,
     xkbcommon,
+    math,
   ],
   install: true,
 )

util.c

@@ -6,6 +6,8 @@
  * See the LICENSE file accompanying this file.
  */
 
+#include <math.h>
+
 #include "util.h"
 
 int