bugfix: avoid naive use of 'putenv' by providing 'FbTk::App::setenv()'

to quote from 'man putenv':

   The string pointed to by string becomes part of the environment,
   so altering the string changes the environment.

so, using putenv like

   {
      std::string foo("FOO=bar");
      putenv(foo.c_str());
   }

is wrong and leads to a potentially corrupted environment. valgrind
complaint correctly.

FbTk::App seems to be the appropriate place to hold '::seten()'
because it alters the environment of the application.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/FbTk/App.hh b/src/FbTk/App.hh
index d878661..b83dd15 100644
--- a/src/FbTk/App.hh
+++ b/src/FbTk/App.hh
@@ -53,6 +53,11 @@ public:
     /// forces an end to event loop
     void end();
     bool done() const { return m_done; }
+
+    // the setenv()-routine is not everywhere available and
+    // putenv() doesnt manage the strings in the environment
+    // and hence we have to do that on our own to avoid memleaking
+    static bool setenv(const char* key, const char* value);
 private:
     static App *s_app;
     bool m_done;