diff --git a/ChangeLog b/ChangeLog
index bffcbbab445..256f78f6fb3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2014-10-02  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* configure.ac: Port to strict POSIX shells on non-MinGW (Bug#18612).
+
 2014-09-21  Jan Djärv  <jan.h.d@swipnet.se>
 
 	* configure.ac: Increase headerpad_extra to 1000, update the comment
diff --git a/configure.ac b/configure.ac
index dd70700bacb..20acc46a1b3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -35,7 +35,8 @@ then
       # "/c/foo/bar", to simplify later conversions to native Windows
       # format ("c:/foo/bar")
       srcdir=`cd "${srcdir}" && pwd -W`
-      srcdir="/${srcdir:0:1}${srcdir:2}"
+      # 'eval' pacifies strict POSIX non-MinGW shells (Bug#18612).
+      eval 'srcdir="/${srcdir:0:1}${srcdir:2}"'
       ;;
   esac
 fi