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, 2 insertions, 2 deletions

diff --git a/src/libexpr/common-opts.cc b/src/libexpr/common-opts.cc
index 0ee889a995ef..9b3421f6c4bc 100644
--- a/src/libexpr/common-opts.cc
+++ b/src/libexpr/common-opts.cc
@@ -13,7 +13,7 @@ bool parseOptionArg(const string & arg, Strings::iterator & i,
     if (arg != "--arg" && arg != "--argstr") return false;
 
     UsageError error(format("`%1%' requires two arguments") % arg);
-    
+
     if (i == argsEnd) throw error;
     string name = *i++;
     if (i == argsEnd) throw error;
@@ -39,7 +39,7 @@ bool parseSearchPathArg(const string & arg, Strings::iterator & i,
 {
     if (arg != "-I") return false;
     if (i == argsEnd) throw UsageError(format("`%1%' requires an argument") % arg);;
-    state.addToSearchPath(*i++);
+    state.addToSearchPath(*i++, true);
     return true;
 }