From 535040aab88508e4c43b7d29a96ea74aa5d0883a Mon Sep 17 00:00:00 2001
From: Chris Wong <lambda.fairy@gmail.com>
Date: Fri, 8 May 2015 22:26:26 +1200
Subject: [PATCH] Generate CFG_FILENAME_EXTRA from the version

The code takes a prefix of the MD5 hash of the version string.

Since the hash command differs across GNU and BSD platforms, we scan for
the right one in the configure script.

Closes #25007
---
 configure  | 14 ++++++++++++++
 mk/main.mk |  4 +++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index 9aebfe07967..814626481f5 100755
--- a/configure
+++ b/configure
@@ -709,6 +709,20 @@ else
     probe_need CFG_GIT     git
 fi
 
+# Use `md5sum` on GNU platforms, or `md5 -q` on BSD
+probe CFG_MD5              md5
+probe CFG_MD5SUM           md5sum
+if [ -n "$CFG_MD5" ]
+then
+    CFG_HASH_COMMAND="$CFG_MD5 -q | head -c 8"
+elif [ -n "$CFG_MD5SUM" ]
+then
+    CFG_HASH_COMMAND="$CFG_MD5SUM | head -c 8"
+else
+    err 'could not find one of: md5 md5sum'
+fi
+putvar CFG_HASH_COMMAND
+
 probe CFG_CLANG            clang++
 probe CFG_CCACHE           ccache
 probe CFG_GCC              gcc
diff --git a/mk/main.mk b/mk/main.mk
index 9ac96aa90f6..20323adaea1 100644
--- a/mk/main.mk
+++ b/mk/main.mk
@@ -20,7 +20,9 @@ CFG_RELEASE_NUM=1.1.0
 # versions (section 9)
 CFG_PRERELEASE_VERSION=.1
 
-CFG_FILENAME_EXTRA=4e7c5e5c
+# Append a version-dependent hash to each library, so we can install different
+# versions in the same place
+CFG_FILENAME_EXTRA=$(shell echo -n $(CFG_RELEASE) | $(CFG_HASH_COMMAND))
 
 ifeq ($(CFG_RELEASE_CHANNEL),stable)
 # This is the normal semver version string, e.g. "0.12.0", "0.12.0-nightly"