distro FEATURE debian packaging

Debian packaging files from libyang2-debian-packaging branch
by Ondřej Surý with minimal changes for apkg.

    apkg build -i

results in installable Debian packages on Debian/Ubuntu systems.
diff --git a/distro/pkg/deb/control b/distro/pkg/deb/control
new file mode 100644
index 0000000..76cad6c
--- /dev/null
+++ b/distro/pkg/deb/control
@@ -0,0 +1,71 @@
+Source: libyang2
+Section: libs
+Homepage: https://github.com/CESNET/libyang/
+Maintainer: Ondřej Surý <ondrej@debian.org>
+Priority: optional
+Standards-Version: 4.5.0
+Build-Depends: cmake,
+               debhelper (>= 10),
+               libcmocka-dev <!nocheck>,
+               libpcre2-dev,
+               pkg-config
+Vcs-Browser: https://github.com/CESNET/libyang/tree/libyang2
+Vcs-Git: https://github.com/CESNET/libyang.git -b libyang2
+
+Package: libyang2
+Depends: ${misc:Depends},
+         ${shlibs:Depends}
+Architecture: any
+Description: parser toolkit for IETF YANG data modeling - runtime
+ Libyang implements functions to process schemas expressed in the
+ YANG data modeling language defined by the IETF in RFCs 6020/7950.
+ Schemas expressed in this language primarily describe configuration
+ used by larger network equipment like routers and switches.
+ .
+ In addition to handling the schemas itself, the library also provides
+ functions to process data described by the schemas.
+ .
+ The library is implemented in C and provides an API for other software
+ to use in processing configurations.
+
+Package: libyang2-dev
+Depends: libpcre3-dev,
+         libyang2 (= ${binary:Version}),
+         ${misc:Depends}
+Conflicts: libyang-dev
+Section: libdevel
+Architecture: any
+Description: parser toolkit for IETF YANG data modeling - development files
+ Libyang implements functions to process schemas expressed in the
+ YANG data modeling language defined by the IETF in RFCs 6020/7950.
+ Schemas expressed in this language primarily describe configuration
+ used by larger network equipment like routers and switches.
+ .
+ In addition to handling the schemas itself, the library also provides
+ functions to process data described by the schemas.
+ .
+ This package contains the C headers, a pkgconfig file, and .so entry point
+ for libyang.
+
+Package: libyang2-tools
+Depends: libyang2 (= ${binary:Version}),
+         ${misc:Depends},
+         ${shlibs:Depends}
+Breaks: libyang-tools (<< ${source:Version})
+Replaces: libyang-tools (<< ${source:Version})
+Section: devel
+Architecture: any
+Description: parser toolkit for IETF YANG data modeling - executable tools
+ This package provides the "yanglint" and "yangre" tools which can be used
+ during the creation of IETF YANG schemas.  The tools are not generally
+ useful for normal operation where libyang primarily processes configuration
+ data, not schemas.
+
+Package: libyang-tools
+Depends: libyang2-tools (>= ${source:Version}),
+         ${misc:Depends}
+Section: oldlibs
+Architecture: all
+Description: parser toolkit for IETF YANG data modeling [dummy package]
+ This is empty dependency package to pull the executable tools.  It's
+ safe to remove.