[nautilus] build: Warn on duplicate conditions in conditional statements

[Ernestas Kulik <ernestask src gnome org>]

commit 894cda329c34ab04afbc3aa840f5b62101fe496e
Author: Ernestas Kulik <ernestask gnome org>
Date:   Mon May 28 12:59:33 2018 +0300

    build: Warn on duplicate conditions in conditional statements
    
    Since we’re handling duplicate branches, this makes sense.

 meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/meson.build b/meson.build
index ed2e355ab..4e9be097b 100644
--- a/meson.build
+++ b/meson.build
@@ -23,6 +23,7 @@ add_project_arguments(
   cc.get_supported_arguments([
     '-Wall',
     '-Wduplicated-branches',
+    '-Wduplicated-cond',
     '-Wlogical-op',
     '-Werror=declaration-after-statement',
     '-Werror=empty-body',