diff --git a/src/tools/pgindent/pgindent b/src/tools/pgindent/pgindent
index ee30da799b4..fa2041dc34b 100755
--- a/src/tools/pgindent/pgindent
+++ b/src/tools/pgindent/pgindent
@@ -209,6 +209,20 @@ sub process_exclude
 	return;
 }
 
+# Does the given directory look like the top of a build tree?
+sub is_build_dir
+{
+	my $dir = shift;
+
+	# This is how Meson itself identifies a build tree.
+	return 1 if -f "$dir/meson-private/coredata.dat";
+
+	# Autoconf VPATH build directory
+	return 1 if -f "$dir/config.status" && !-f "$dir/configure.ac";
+
+	return 0;
+}
+
 sub read_source
 {
 	my $source_filename = shift;
@@ -467,8 +481,22 @@ check_indent();
 
 my $wanted = sub {
 	my ($dev, $ino, $mode, $nlink, $uid, $gid);
-	(($dev, $ino, $mode, $nlink, $uid, $gid) = lstat($_))
-	  && -f _
+	return unless (($dev, $ino, $mode, $nlink, $uid, $gid) = lstat($_));
+
+	# Don't even descend into a build tree.
+	#
+	# Note that File::Find has chdir'd into the containing directory,
+	# so $_ is what we must test.  For a directory named on the
+	# command line, $_ is ".", and we process such a directory even if
+	# it is a build tree, since that was asked for explicitly.
+	if (-d _)
+	{
+		$File::Find::prune = 1
+		  if ($_ ne "." && is_build_dir($_));
+		return;
+	}
+
+	-f _
 	  && /^.*\.[ch]\z/s
 	  && push(@files, $File::Find::name);
 };
diff --git a/src/tools/pgindent/pgindent.man b/src/tools/pgindent/pgindent.man
index caab5cde914..358ba096447 100644
--- a/src/tools/pgindent/pgindent.man
+++ b/src/tools/pgindent/pgindent.man
@@ -31,6 +31,11 @@ find the file src/tools/pgindent/exclude_file_patterns. The --excludes option
 can be used more than once to specify multiple files containing exclusion
 patterns.
 
+Build directories that pgindent comes across while scanning a
+directory are recognized and skipped automatically.  A build directory
+named directly on the command line is still processed, on the
+assumption that this was asked for on purpose.
+
 There are also two non-destructive modes of pgindent. If given the --diff
 option pgindent will show the changes it would make, but doesn't actually make
 them. If given instead the --check option, pgindent will exit with a status of