From 3444c77254126f63729ccee66523b2677ba0b51e Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <campbell@mumble.net>
Date: Mon, 2 Nov 2009 11:29:03 -0500
Subject: [PATCH] Make the compiler/configure script idempotent.

---
 src/compiler/configure | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/compiler/configure b/src/compiler/configure
index e7f57d023..c4e9ac5d6 100755
--- a/src/compiler/configure
+++ b/src/compiler/configure
@@ -42,11 +42,23 @@ while test $# -gt 0; do
 done
 MACHINE=`./choose-machine.sh "${MACHINE}"`
 
-CMD="rm -f machine"
-echo "${CMD}"; eval "${CMD}"
+make_link ()
+{
+    local target link
+    target="${1}"
+    link="${2}"
+    if [ -e "${link}" -a ! -L "${link}" ]; then
+	cat <<EOF >&2
+${link} is not a symbolic link; refusing to clobber it.
+EOF
+	exit 1
+    else
+	CMDS="rm -f ${link} && ln -s ${target} ${link}"
+	echo "${CMDS}"; eval "${CMDS}"
+    fi
+}
 
-CMD="ln -s machines/${MACHINE} machine"
-echo "${CMD}"; eval "${CMD}"
+make_link "machines/${MACHINE}" machine
 
 LINKS="compiler.cbf compiler.pkg compiler.sf make.com"
 if test "${MACHINE}" = C; then
@@ -54,8 +66,5 @@ if test "${MACHINE}" = C; then
 fi
 
 for FN in ${LINKS}; do
-    if [ ! -f "${FN}" ]; then
-	CMD="ln -s machine/${FN} ."
-	echo "${CMD}"; eval "${CMD}"
-    fi
+    make_link "machine/${FN}" "${FN}"
 done
-- 
2.25.1