Re: relocate.cc: Introduce new command `set?'. (issue 345160043 by address@hidden)

[lemzwerg]

Reviewers: dak,

Message:
> Where/how is that being used?  Wouldn't this want documenting?

It's nowhere documented, which pretty nicely describes the state of gub
in total...  This feature gets only activated if you configure with
`--enable-relocation` (which you normally won't do).

I will document this central part of gub builds later on, together with
the other relocation commands.

Description:
relocate.cc: Introduce new command `set?'.

Contrary to `set', `set?' won't override environment variables that are
already set.

We need this for reproducable builds, in particular with gub: The
standard
fontconfig setup includes font files like `~/.fonts' or `/usr/share',
which
obviously must not be used.  Up to now, the `fontconfig.reloc' file in
gub
uses the `set' relocation command, which doesn't allow gub to replace
the
fontconfig configuration file with a temporary alternative while
building
test files or documentation.  Future changes in gub will use `set?'
instead.

Please review this at https://codereview.appspot.com/345160043/

Affected files (+4, -0 lines):
  M lily/relocate.cc


Index: lily/relocate.cc
diff --git a/lily/relocate.cc b/lily/relocate.cc
index  
879377a1cc0928bae14c6fd92c5fd8f032eacac2..02776ff414b382e2f712e53c1b1bce05b0a701aa  
100644
--- a/lily/relocate.cc
+++ b/lily/relocate.cc
@@ -63,6 +63,8 @@ sane_putenv (char const *key, const string &value, bool  
overwrite)
       */
       return retval;
     }
+  else
+    debug_output (_f ("%s not overwritten\n", key));

   return -1;
 }
@@ -371,6 +373,8 @@ read_relocation_file (const string &filename)

       if (command == "set")
         sane_putenv (variable.c_str (), value, true);
+      if (command == "set?")
+        sane_putenv (variable.c_str (), value, false);
       else if (command == "setdir")
         set_env_dir (variable.c_str (), value);
       else if (command == "setfile")