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, 1 insertions, 2 deletions

diff --git a/src/main.cc b/src/main.cc
index 300826e..28302d4 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -219,8 +219,7 @@ static void parseOptions(int argc, char** argv, Options& opts) {
             }
 
             opts.session_display = argv[i];
-            string display_env = "DISPLAY=" + opts.session_display;
-            if (putenv(const_cast<char *>(display_env.c_str()))) {
+            if (!FbTk::App::setenv("DISPLAY", argv[i])) {
                 cerr<<_FB_CONSOLETEXT(main, WarnDisplayEnv,
                                 "warning: couldn't set environment variable 'DISPLAY'",
                               "")<<endl;