meson: link with -lrt if needed for clock_gettime

This is already done in autotools, and fixes the build with glibc < 2.17.

Signed-off-by: Loïc Yhuel <loic.yhuel@softathome.com>

meson.build

@@ -56,6 +56,14 @@ if get_option('libraries')
 			error('@0@ is needed to compile Wayland libraries'.format(d['symbol']))
 		endif
 	endforeach
+
+	rt_dep = []
+	if not cc.has_function('clock_gettime', prefix: '#include <time.h>')
+		rt_dep = cc.find_library('rt')
+		if not cc.has_function('clock_gettime', prefix: '#include <time.h>', dependencies: rt_dep)
+			error('clock_gettime not found')
+		endif
+	endif
 endif
 
 scanner_deps = [ dependency('expat') ]

src/meson.build

@@ -77,7 +77,7 @@ if get_option('libraries')
 			'connection.c',
 			'wayland-os.c'
 		],
-		dependencies: [ ffi_dep, ]
+		dependencies: [ ffi_dep, rt_dep ]
 	)
 
 	wayland_private_dep = declare_dependency(
@@ -155,7 +155,8 @@ if get_option('libraries')
 			wayland_private_dep,
 			wayland_util_dep,
 			mathlib_dep,
-			threads_dep
+			threads_dep,
+			rt_dep
 		],
 		include_directories: root_inc,
 		install: true

tests/meson.build

@@ -54,7 +54,7 @@ benchmark(
 	executable(
 		'fixed-benchmark',
 		'fixed-benchmark.c',
-		dependencies: test_runner_dep
+		dependencies: [ test_runner_dep, rt_dep ]
 	)
 )