Hi Stefan,

When activating the "--with-mpx" flag in ./configure, a check is also performed to see if the compiler is GCC version 5.1 or higher in order to support MPX (and an appropriate error is shown, indicating that the compiler version is wrong). Setting the flags manually will only result in a compiler error.

Also, it might not be obvious for the user from the GCC documentation that both "-fcheck-pointer-bounds" and "-mmpx" flags are needed to enable MPX instrumentation, so adding the "--with-mpx" flag to configure will make it easier to use this feature.