Warn about missing -I paths

Fixes #121.  Note that we don't warn about missing $NIX_PATH entries
because it's intended that some may be missing (cf. the default
$NIX_PATH on NixOS, which includes paths like /etc/nixos/nixpkgs for
backward compatibility).

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 5ae5a1e3cf..6da89c58a6 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -120,7 +120,7 @@ public:
     EvalState();
     ~EvalState();
 
-    void addToSearchPath(const string & s);
+    void addToSearchPath(const string & s, bool warn = false);
 
     /* Parse a Nix expression from the specified file. */
     Expr * parseExprFromFile(const Path & path);