meson: add build/man/man and build/man/html to build and display pages

Man page generation is generally very slow. I prefer to use -Dman=false when
developing systemd, and only build specific pages when introducing changes.
Those two little helper tools make it easy:

$ build/man/man systemd.link
$ build/man/html systemd.link

will show systemd.link.8 and systemd.link.html from the build directory build/.

1 files changed, 15 insertions, 0 deletions

diff --git a/man/man.in b/man/man.in
new file mode 100755
index 0000000000..5700a642bd
--- /dev/null
+++ b/man/man.in
@@ -0,0 +1,15 @@
+#!/bin/sh
+set -e
+
+if [ -z "$1" ]; then
+    echo "Use: $0 page-name (with no section suffix)"
+    exit 1
+fi
+
+target=$(ninja -C "@BUILD_ROOT@" -t query man/man | grep -E -m1 "man/$1\.[0-9]$" | awk '{print $2}')
+if [ -z "$target" ]; then
+    echo "Cannot find page $1"
+    exit 1
+fi
+ninja -C "@BUILD_ROOT@" "$target"
+exec man build/"$target"