From 26ccaab75a1eae3d71a6497dacc7818f8e62417d Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@sbcglobal.net>
Date: Wed, 2 Sep 2015 13:24:13 -0600
Subject: Makefile variable tracking

---
 .gitignore      |  5 ++++-
 Makefile        | 15 +++++++++++++--
 nshd.service    | 16 ----------------
 nshd.service.in | 16 ++++++++++++++++
 4 files changed, 33 insertions(+), 19 deletions(-)
 delete mode 100644 nshd.service
 create mode 100644 nshd.service.in

diff --git a/.gitignore b/.gitignore
index 0de96dd..131b639 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,6 @@
 /pkg
 /bin
-/src/*.*/
\ No newline at end of file
+/src/*.*/
+/nshd.service
+/.Makefile.var.*
+/.tmp.Makefile.var.*
diff --git a/Makefile b/Makefile
index 492bb7a..15c1c43 100644
--- a/Makefile
+++ b/Makefile
@@ -7,6 +7,9 @@ GOPATH := $(realpath $(dir $(lastword $(MAKEFILE_LIST))))
 
 CFLAGS = -std=c99 -Wall -Wextra -Werror -pedantic
 CGO_CFLAGS = $(CFLAGS) -Wno-unused-parameter
+export CGO_ENABLED = 1
+
+cgo_variables = CGO_ENABLED CGO_CFLAGS CGO_CPPFLAGS CGO_CXXFLAGS CGO_LDFLAGS CC CXX
 
 deps = gopkg.in/yaml.v2
 subdirs = src/nslcd_proto
@@ -18,7 +21,7 @@ include $(addsuffix /Makefile,$(subdirs))
 secondary += 
 download += $(addprefix src/,$(deps))
 generate +=
-build += bin/nshd
+build += bin/nshd nshd.service
 install += $(addprefix $(DESTDIR),$(bindir)/nshd $(systemddir)/system/nshd.socket $(systemddir)/system/nshd.service)
 
 download: $(download)
@@ -40,9 +43,13 @@ uninstall:
 $(foreach d,$(deps),$(eval src/$d: NET; GOPATH='$(GOPATH)' go get -d -u $d))
 .PHONY: NET
 
-bin/nshd: $(download) $(generate) $(shell find src -name .git -prune -o -print)
+bin/nshd: $(download) $(generate) $(shell find src -name .git -prune -o -print) $(addprefix .Makefile.var.,$(cgo_variables))
+	@true $(foreach f,$(filter .Makefile.var.%,$^), && test $@ -nt $f ) || rm -rf -- bin pkg
 	GOPATH='$(GOPATH)' CGO_CFLAGS='$(CGO_CFLAGS)' go install nshd
 
+nshd.service: nshd.service.in .Makefile.var.bindir
+	< $< sed 's|@bindir@|$(bindir)|g' > $@
+
 $(DESTDIR)$(bindir)/%: bin/%
 	install -Dm755 $< $@
 $(DESTDIR)$(systemddir)/system/%.socket: %.socket
@@ -50,5 +57,9 @@ $(DESTDIR)$(systemddir)/system/%.socket: %.socket
 $(DESTDIR)$(systemddir)/system/%.service: %.service
 	install -Dm644 $< $@
 
+.Makefile.var.%: FORCE
+	@printf '%s' '$($*)' > .tmp$@ && { cmp -s .tmp$@ $@ && rm -f -- .tmp$@ || mv -Tf .tmp$@ $@; } || { rm -f -- .tmp$@; false; }
+.PHONY: FORCE
+
 .SECONDARY:
 .DELETE_ON_ERROR:
diff --git a/nshd.service b/nshd.service
deleted file mode 100644
index 0af363d..0000000
--- a/nshd.service
+++ /dev/null
@@ -1,16 +0,0 @@
-[Unit]
-Description=Parabola hackers.git authentication
-Requires=nshd.socket
-After=syslog.target nshd.socket
-
-[Service]
-Type=notify
-Sockets=nshd.socket
-ExecStart=/usr/bin/nshd
-
-User=nshd
-Group=nshd
-
-[Install]
-WantedBy=multi-user.target
-
diff --git a/nshd.service.in b/nshd.service.in
new file mode 100644
index 0000000..032976b
--- /dev/null
+++ b/nshd.service.in
@@ -0,0 +1,16 @@
+[Unit]
+Description=Parabola hackers.git authentication
+Requires=nshd.socket
+After=syslog.target nshd.socket
+
+[Service]
+Type=notify
+Sockets=nshd.socket
+ExecStart=@bindir@/nshd
+
+User=nshd
+Group=nshd
+
+[Install]
+WantedBy=multi-user.target
+
-- 
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