Non-trivial merge.

Skipped merging the following changes due to :
- ba4a7221
  Fix GDB unit tests for 5.0 branch
  Problem: Same patch for master already got applied
- 16bd7996
  Turn off gdb disable-randomization when testing
  Problem: No testing mode (m_testing variable) anymore?
    (didn't compile, please re-apply)

@Peifeng: Please double-check master

CCMAIL: 7437103@gmail.com