[PATCH] cmd.mk, install-man.mk: Allow installing link pages as symlinks

[Alejandro Colomar <alx.manpages@gmail.com>]

We keep them as .so "includes" in our source code, but if some
distribution wants to have them as symlinks in their filesystem, make it
easy for them to install as such, by specifying 'LINK_PAGES=symlink'.

Signed-off-by: Alejandro Colomar <alx@kernel.org>
---

Hi!

I'm going to add support for installing link pages as symlinks.  Debian
installs them this way, so I think it makes sense to help distributors
use our upstream build system to install in their preferred way, since
otherwise, to be more useful.

Here's the implementation I came up with, but I'd like to hear comments
about the interface (the LINK_PAGES variable).  Would you make it
different?

Thanks!

Alex


 lib/cmd.mk         | 1 +
 lib/install-man.mk | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/lib/cmd.mk b/lib/cmd.mk
index 17f3a8ee5..9cd09fe89 100644
--- a/lib/cmd.mk
+++ b/lib/cmd.mk
@@ -16,6 +16,7 @@ GREP       := grep
 GZIP       := gzip
 HEAD       := head
 INSTALL    := install
+LN         := ln
 LOCALE     := locale
 PKG-CONFIG := pkg-config
 SED        := sed
diff --git a/lib/install-man.mk b/lib/install-man.mk
index 174f503ca..aaa545290 100644
--- a/lib/install-man.mk
+++ b/lib/install-man.mk
@@ -12,6 +12,9 @@ include $(srcdir)/lib/install.mk
 include $(srcdir)/lib/src.mk
 
 
+LINK_PAGES := so  # Alternatives: "so", "symlink"
+
+
 mandir      := $(datarootdir)/man
 man1dir     := $(mandir)/man1
 man2dir     := $(mandir)/man2
@@ -147,6 +150,12 @@ $(_manpages):
 		-e '/^\.so /s, man7/\(.*\)\.7$$, $(notdir $(man7dir))/\1$(man7ext),' \
 		-e '/^\.so /s, man8/\(.*\)\.8$$, $(notdir $(man8dir))/\1$(man8ext),' \
 		$@
+ifeq ($(LINK_PAGES),symlink)
+	if $(GREP) '^\.so ' <$@ >/dev/null; then \
+		$(SED) 's,^\.so \(.*\),../\1,' <$@ \
+		| $(XARGS) -I tgt $(LN) -fsT tgt $@; \
+	fi
+endif
 
 $(_mandirs): %/.: | $$(dir %). $(_mandir)/.
 
-- 
2.39.2