From fec16a3bfba178ac786656845ad19954643ce88c Mon Sep 17 00:00:00 2001
From: Jean-Francois Dockes <jf@dockes.org>
Date: Mon, 25 Nov 2019 11:54:51 +0100
Subject: [PATCH] configure: default to single-threaded on macosx

---
 src/configure.ac | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/configure.ac b/src/configure.ac
index 09bbb880..3fbf649b 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -208,13 +208,20 @@ if test X$withFam != Xno ; then
 fi
 
 # Enable use of threads in the indexing pipeline.  
-# This is disabled by default as we usually care little about indexing 
-# absolute performance (more about impact on usability and total 
-# resources used).
-AC_ARG_ENABLE(idxthreads,
-    AC_HELP_STRING([--disable-idxthreads],
-   [Disable multithread indexing.]),
+# Disabled by default on OS X as this actually hurts performance.
+# Also disabled on Windows (which does not use configure, see autoconfig-win.h)
+case ${host_os} in
+    darwin*)
+    AC_ARG_ENABLE(idxthreads,
+        [--enable-idxthreads Enable multithread indexing.],
+        idxthreadsEnabled=$enableval, idxthreadsEnabled=no)
+      ;;
+    *)
+    AC_ARG_ENABLE(idxthreads,
+       [--disable-idxthreads  Disable multithread indexing.],
         idxthreadsEnabled=$enableval, idxthreadsEnabled=yes)
+      ;;
+esac
 AM_CONDITIONAL(NOTHREADS, [test X$idxthreadsEnabled = Xno])
 if test X$idxthreadsEnabled = Xyes ; then
   AC_DEFINE(IDX_THREADS, 1, [Use multiple threads for indexing])