TOOL-11726 gdb-python: add build-dependencies to control file and stop requiring python 3.6

Reviewed at: http://reviews.delphix.com/r/70235/

Author: pzakha

debian/control

@@ -2,6 +2,24 @@ Source: gdb-python
 Section: misc
 Priority: optional
 Maintainer: Delphix Engineering <eng@delphix.com>
+Build-Depends:
+	autoconf,
+	automake,
+	bison,
+	dh-python,
+	flex,
+	git,
+	liblzo2-dev,
+	libmpfr-dev,
+	libsnappy1v5,
+	libtool,
+	pkg-config,
+	python3-distutils,
+	python3-future,
+	python3-pyelftools,
+	python3-dev,
+	texinfo,
+	zlib1g-dev
 Standards-Version: 4.1.2
 
 Package: gdb-python

debian/rules

@@ -3,11 +3,11 @@
 SOURCE_NAME := $(shell dpkg-parsechangelog | sed -rne "s,^Source: (.*),\1,p")
 
 %:
-	dh $@
+	dh $@ --with python3
 
 override_dh_auto_configure:
 	dh_auto_configure -- \
-		--with-python=/usr/bin/python3.6 \
+		--with-python=/usr/bin/python3 \
 		--prefix=/opt/gdb-python
 
 override_dh_auto_build: