meson: correctly detect posix_fallocate

Signed-off-by: Chris Hofstaedtler <zeha@debian.org>

diff --git a/meson.build b/meson.build
index 316c265b478af54805418b87ddc4cdc96f529d29..5a2838628f5bdd04995b28964d4e789853a1a2cb 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -882,6 +882,7 @@ have = cc.links(code, name : 'fallocate() function')
 conf.set('HAVE_FALLOCATE', have ? 1 : false)
 
 code = '''
+#define _POSIX_C_SOURCE 200112L
 #include <unistd.h>
 #include <fcntl.h>