Bug#987528: ghdl-gcc: Missing Built-Using for gcc

[Adrian Bunk]

Package: ghdl-gcc
Version: 0.35+git20181129+dfsg-3
Severity: serious

ghdl-gcc needs a Built-Using for gcc:
https://www.debian.org/doc/debian-policy/ch-relationships.html#additional-source-packages-used-to-build-the-binary-built-using