Restore partial failure handling with stty, fixes #889

Author: gnodet

terminal/src/main/java/org/jline/terminal/impl/exec/ExecPty.java

@@ -101,7 +101,19 @@ protected void doSetAttr(Attributes attr) throws IOException {
                 commands.add(1, OSUtils.STTY_F_OPTION);
                 commands.add(2, getName());
             }
-            exec(systemStream != null, commands.toArray(new String[0]));
+            try {
+                exec(systemStream != null, commands.toArray(new String[0]));
+            } catch (IOException e) {
+                // Handle partial failures with GNU stty, see #97
+                if (e.toString().contains("unable to perform all requested operations")) {
+                    commands = getFlagsToSet(attr, getAttr());
+                    if (!commands.isEmpty()) {
+                        throw new IOException("Could not set the following flags: " + String.join(", ", commands), e);
+                    }
+                } else {
+                    throw e;
+                }
+            }
         }
     }