Bug#876589: libtasn1-6 FTBFS with gtk-doc-tools 1.26: gtkdoc-mktmpl is no longer available

[Adrian Bunk]

Source: libtasn1-6
Version: 4.12-2.1
Severity: serious

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/libtasn1-6.html

...
Making all in reference
make[5]: Entering directory '/build/1st/libtasn1-6-4.12/doc/reference'
  DOC   Scanning header files
  DOC   Rebuilding template files
/bin/bash: gtkdoc-mktmpl: command not found
Makefile:1240: recipe for target 'tmpl-build.stamp' failed
make[5]: *** [tmpl-build.stamp] Error 127