added wxGet/Set/UnsetEnv() for Unix

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@8837 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/utilsunx.cpp

@@ -869,6 +869,33 @@ long wxGetFreeMemory()
     return -1;
 }
 
+// ----------------------------------------------------------------------------
+// env vars
+// ----------------------------------------------------------------------------
+
+bool wxSetEnv(const wxString& variable, const wxChar *value)
+{
+#if defined(HAVE_SETENV)
+    return setenv(variable.mb_str(), value ? wxString(value).mb_str().data()
+                                           : NULL, 1 /* overwrite */) == 0;
+#elif defined(HAVE_PUTENV)
+    wxString s = variable;
+    if ( value )
+        s << _T('=') << value;
+
+    // transform to ANSI
+    const char *p = s.mb_str();
+
+    // the string will be free()d by libc
+    char *buf = (char *)malloc(strlen(p) + 1);
+    strcpy(buf, p);
+
+    return putenv(buf) == 0;
+#else // no way to set an env var
+    return FALSE;
+#endif
+}
+
 // ----------------------------------------------------------------------------
 // signal handling
 // ----------------------------------------------------------------------------