compiler warnings

/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘void Mms::sendNotifyResponse(const QString&, const QString&)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:167:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘149’ to ‘'\37777777625'’ [-Woverflow]
  167 |     data.append(MMS_HEADER_STATUS);
      |                 ^~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:170:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘145’ to ‘'\37777777621'’ [-Woverflow]
  170 |     data.append(MMS_HEADER_REPORT_ALLOWED);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘void Mms::sendDeliveryAcknowledgement(const QString&)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:181:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘145’ to ‘'\37777777621'’ [-Woverflow]
  181 |     data.append(MMS_HEADER_REPORT_ALLOWED);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘void Mms::sendReadReport(const QString&)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:193:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘151’ to ‘'\37777777627'’ [-Woverflow]
  193 |     data.append(MMS_HEADER_TO);
      |                 ^~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:196:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘137’ to ‘'\37777777611'’ [-Woverflow]
  196 |     data.append(MMS_HEADER_FROM);
      |                 ^~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:199:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘155’ to ‘'\37777777633'’ [-Woverflow]
  199 |     data.append(MMS_HEADER_READ_STATUS);
      |                 ^~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:200:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘128’ to ‘'\37777777600'’ [-Woverflow]
  200 |     data.append(MMS_CODE_READ); //MMS_CODE_DELETE_WITHOUT_READ
      |                 ^~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘void Mms::sendCancelResponse(const QString&)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:214:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘191’ to ‘'\37777777677'’ [-Woverflow]
  214 |     data.append(MMS_HEADER_CANCEL_STATUS);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:215:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘128’ to ‘'\37777777600'’ [-Woverflow]
  215 |     data.append(MMS_CODE_CANCEL_REQUEST_SUCCESSFULLY_RECEIVED);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘void Mms::encodeMessage(MmsMessage&, QByteArray&, const QStringList&, long int)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:318:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘133’ to ‘'\37777777605'’ [-Woverflow]
  318 |     data.append(MMS_HEADER_DATE);
      |                 ^~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:321:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘137’ to ‘'\37777777611'’ [-Woverflow]
  321 |     data.append(MMS_HEADER_FROM);
      |                 ^~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:326:21: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘151’ to ‘'\37777777627'’ [-Woverflow]
  326 |         data.append(MMS_HEADER_TO);
      |                     ^~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:340:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘138’ to ‘'\37777777612'’ [-Woverflow]
  340 |     data.append(MMS_HEADER_MESSAGE_CLASS);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:341:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘128’ to ‘'\37777777600'’ [-Woverflow]
  341 |     data.append(MMS_CODE_MESSAGE_CLASS_PERSONAL);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:351:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘144’ to ‘'\37777777620'’ [-Woverflow]
  351 |     data.append(MMS_HEADER_READ_REPORT);
      |                 ^~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:354:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘134’ to ‘'\37777777606'’ [-Woverflow]
  354 |     data.append(MMS_HEADER_DELIVERY_REPORT);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:357:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘132’ to ‘'\37777777604'’ [-Woverflow]
  357 |     data.append(MMS_HEADER_CONTENT_TYPE);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:360:21: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘179’ to ‘'\37777777663'’ [-Woverflow]
  360 |         data.append(MMS_CODE_MULTIPART_RELATED);
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:363:21: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘138’ to ‘'\37777777612'’ [-Woverflow]
  363 |         data.append(MMS_PARAM_START);
      |                     ^~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:365:21: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘137’ to ‘'\37777777611'’ [-Woverflow]
  365 |         data.append(MMS_PARAM_TYPE_SPEC);
      |                     ^~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:370:21: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘163’ to ‘'\37777777643'’ [-Woverflow]
  370 |         data.append(MMS_CODE_MULTIPART_MIXED);
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:473:23: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘192’ to ‘'\37777777700'’ [-Woverflow]
  473 |         params.append(0xC0);
      |                       ^~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:476:23: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘142’ to ‘'\37777777616'’ [-Woverflow]
  476 |         params.append(0x8E);
      |                       ^~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘QByteArray Mms::encodeHeaderPrefix(const QString&, const QString&, bool)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:539:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘140’ to ‘'\37777777614'’ [-Woverflow]
  539 |     data.append(MMS_HEADER_MESSAGE_TYPE);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:545:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘141’ to ‘'\37777777615'’ [-Woverflow]
  545 |     data.append(MMS_HEADER_VERSION);
      |                 ^~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:546:17: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘147’ to ‘'\37777777623'’ [-Woverflow]
  546 |     data.append(MMS_CODE_VERSION);
      |                 ^~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘QByteArray Mms::encodeEncodedStringValue(const QString&)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:932:18: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘131’ to ‘'\37777777603'’ [-Woverflow]
  932 |     bytes.append(MMS_HEADER_CONTENT_LOCATION);
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘QByteArray Mms::encodeFromValue(const QString&)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:944:22: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘129’ to ‘'\37777777601'’ [-Woverflow]
  944 |         bytes.append(MMS_CODE_INSERT_ADDRESS_TOKEN);
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:948:22: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘128’ to ‘'\37777777600'’ [-Woverflow]
  948 |         bytes.append(MMS_CODE_ADDRESS_PRESENT_TOKEN);
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp: In member function ‘QByteArray Mms::encodePart(const QByteArray&, const QString&, const QByteArray&, const QByteArray&)’:
/home/jonahb/kde/src/spacebar/lib/mms/mms.cpp:974:19: warning: overflow in conversion from ‘int’ to ‘char’ changes value from ‘133’ to ‘'\37777777605'’ [-Woverflow]
  974 |     header.append(MMS_PARAM_NAME);
      |                   ^~~~~~~~~~~~~~