Merge #14515: doc: Update OpenBSD build guide for 6.4

33ae985 doc: Update OpenBSD build guide for 6.4 (fanquake)
6d247b1 gitignore contents of db4 folder (Marty Jones)

Pull request description:

  Includes a commit from #14314.
  The `disable-dependency-tracking ` workaround is still required to run `./configure` (cc #14404).
  `gmake check -j4` pass.
  `src/bitcoind` runs and "starts" syncing.

Tree-SHA512: 72d78eb0d94fc4f2bbcf901d867f10f0e85d8a4f43969c598953278343ed826a26d1ebe6772dcc0fbd1fc608e88b7c86e31656232c1efb0656c537176fb9de4c

.gitignore

@@ -116,3 +116,6 @@ test/cache/*
 
 libbitcoinconsensus.pc
 contrib/devtools/split-debug.sh
+
+# Output from running db4 installation
+db4/

doc/build-openbsd.md

@@ -1,6 +1,6 @@
 OpenBSD build guide
 ======================
-(updated for OpenBSD 6.3)
+(updated for OpenBSD 6.4)
 
 This guide describes how to build bitcoind and command-line utilities on OpenBSD.
 
@@ -14,7 +14,7 @@ Run the following as root to install the base dependencies for building:
 ```bash
 pkg_add git gmake libevent libtool boost
 pkg_add autoconf # (select highest version, e.g. 2.69)
-pkg_add automake # (select highest version, e.g. 1.15)
+pkg_add automake # (select highest version, e.g. 1.16)
 pkg_add python # (select highest version, e.g. 3.6)
 
 git clone https://github.com/bitcoin/bitcoin.git
@@ -60,8 +60,8 @@ Preparation:
 export AUTOCONF_VERSION=2.69
 
 # Replace this with the automake version that you installed. Include only
-# the major and minor parts of the version: use "1.15" for "automake-1.15.1".
-export AUTOMAKE_VERSION=1.15
+# the major and minor parts of the version: use "1.16" for "automake-1.16.1".
+export AUTOMAKE_VERSION=1.16
 
 ./autogen.sh
 ```