[PATCH] build: add "symlink-install" target

[Eric Wong <e@80x24.org>]

This is useful for users relying on system Ruby and lack
permissions to install gems.
---
 GNUmakefile | 14 +++++++++++++-
 dtas.sh     |  7 +++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100755 dtas.sh

diff --git a/GNUmakefile b/GNUmakefile
index e5914b2..084a2d8 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -1,4 +1,4 @@
-# Copyright (C) 2013-2020 all contributors <dtas-all@nongnu.org>
+# Copyright (C) 2013-2021 all contributors <dtas-all@nongnu.org>
 # License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
 all::
 pkg = dtas
@@ -74,5 +74,17 @@ $(pkgtgz): .tgz-manifest
 
 package: $(pkgtgz) $(pkggem)
 
+# Install symlinks to ~/bin (which is hopefuly in PATH) which point to
+# this source tree.
+# prefix + bindir matches git.git Makefile:
+prefix = $(HOME)
+bindir = $(prefix)/bin
+symlink-install :
+	mkdir -p $(bindir)
+	dtas=$(CURDIR)/dtas.sh && cd $(bindir) && \
+	for x in $(CURDIR)/bin/*; do \
+		ln -sf "$$dtas" $$(basename "$$x"); \
+	done
+
 .PHONY: all .FORCE-GIT-VERSION-FILE test $(test_units) NEWS
 .PHONY: check-warnings fix-perms
diff --git a/dtas.sh b/dtas.sh
new file mode 100755
index 0000000..d3ea5e1
--- /dev/null
+++ b/dtas.sh
@@ -0,0 +1,7 @@
+#!/bin/sh -e
+# symlink this file to a directory in PATH to run dtas (or anything in bin/*)
+# without needing perms to install globally.  Used by "make symlink-install"
+p=$(realpath "$0" || readlink "$0") # neither is POSIX, but common
+p=$(dirname "$p") c=$(basename "$0") # both are POSIX
+exec ${RUBY-ruby} -I"$p"/lib "$p"/bin/"${c%.sh}" "$@"
+: this script is too short to copyright