[libxml2] Update information about contributing

[Nick Wellnhofer <nwellnhof src gnome org>]

commit c1002101f7e5b5194af50e6d2be38c96054dfef2
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Sun Nov 12 20:06:21 2017 +0100

    Update information about contributing
    
    The contents of the HACKING file were hopelessly outdated. Remove the
    file and start with a CONTRIBUTING document.

 CONTRIBUTING       |   24 ++++++++++++++++++++++++
 HACKING            |   37 -------------------------------------
 README.cvs-commits |    2 +-
 os400/make.sh      |    2 +-
 4 files changed, 26 insertions(+), 39 deletions(-)
---
diff --git a/CONTRIBUTING b/CONTRIBUTING
new file mode 100644
index 0000000..6f7a988
--- /dev/null
+++ b/CONTRIBUTING
@@ -0,0 +1,24 @@
+The current version of the code can be found in the GNOME Git Repository:
+
+    https://git.gnome.org/browse/libxml2/
+
+There's mirror on GitHub:
+
+    https://github.com/GNOME/libxml2
+
+Start discussions and send patches to the mailing list, or file a bug and
+add a patch as attachment.
+
+    https://mail.gnome.org/mailman/listinfo/xml
+    https://bugzilla.gnome.org/enter_bug.cgi?product=libxml2
+
+Format patches with git-format-patch and use plain text attachments
+if possible.
+
+All code must conform to C89 and pass the "make check" tests. Avoid
+compiler warnings and add regression tests if possible.
+
+The .travis.yml file can be used to thoroughly check the build with strict
+compiler flags, ASan and UBSan. Fork the libxml2 mirror on GitHub and set
+up Travis to test the commits you make on your fork.
+
diff --git a/README.cvs-commits b/README.cvs-commits
index a4bd841..9c7bdd0 100644
--- a/README.cvs-commits
+++ b/README.cvs-commits
@@ -1,4 +1,4 @@
- Please read the HACKING file for instructions
+ Please read the CONTRIBUTING file for instructions
 
 Daniel
 
diff --git a/os400/make.sh b/os400/make.sh
index 95a35a2..860365e 100644
--- a/os400/make.sh
+++ b/os400/make.sh
@@ -34,7 +34,7 @@ fi
 #       Copy some documentation files if needed.
 
 for TEXT in "${TOPDIR}/AUTHORS" "${TOPDIR}/ChangeLog"                   \
-    "${TOPDIR}/Copyright" "${TOPDIR}/HACKING" "${TOPDIR}/README"        \
+    "${TOPDIR}/Copyright" "${TOPDIR}/CONTRIBUTING" "${TOPDIR}/README"        \
     "${TOPDIR}/MAINTAINERS" "${TOPDIR}/NEWS" "${TOPDIR}/TODO"           \
     "${TOPDIR}/TODO_SCHEMAS" "${TOPDIR}/os400/README400"
 do      if [ -f "${TEXT}" ]