Bug#914663: gxtuner does not trap errors from make

[Helmut Grohne]

Source: gxtuner
Version: 3.0-1
Severity: serious
Justification: policy 4.6

gxtuner's upstream Makefile does not trap errors from the compiler. Most
compiler invocations carry a "-" prefix used for ignoring errors. That
prefix violates policy section 4.6. It also makes debugging build
failures unnecessarily hard and facilitates misbuilds.

Helmut