[nautilus/wip/ernestask/implicit-declaration-of-things] meson.build: Define _XOPEN_SOURCE

[Ernestas Kulik <ernestask src gnome org>]

commit c759f6d60a840befe01d484013cf68a818d7518b
Author: Ernestas Kulik <ekulik redhat com>
Date:   Wed Dec 12 09:01:40 2018 +0100

    meson.build: Define _XOPEN_SOURCE
    
    glibc hides various functions we use for reading user/group/etc. entries
    behind feature-test macros:
    
    
https://sourceware.org/git/?p=glibc.git;a=blob;f=pwd/pwd.h;h=e6d20cd78bcd2f4bb48ba4712b0ebf6674315bf0;hb=HEAD#l67
    
https://sourceware.org/git/?p=glibc.git;a=blob;f=grp/grp.h;h=432a147ebe21f5b0f3c91d6d88f4188f98d15c64;hb=HEAD#l56
    
    Those in turn get defined here:
    
    
https://sourceware.org/git/?p=glibc.git;a=blob;f=include/features.h;h=5bed0a499605a3a26d55443f3c8b7e67de152f74;hb=HEAD#l331

 meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/meson.build b/meson.build
index 4b64239ac..d4908e122 100644
--- a/meson.build
+++ b/meson.build
@@ -27,6 +27,7 @@ add_global_arguments(
 )
 add_project_arguments(
   cc.get_supported_arguments([
+    '-D_XOPEN_SOURCE=500',
     '-Wall',
     '-Wduplicated-branches',
     '-Wlogical-op',