From: Eric Blake <ebb9@byu.net>
Date: Thu, 21 Aug 2008 15:32:21 +0000 (-0600)
Subject: Document another make bug.
X-Git-Tag: v2.63~22
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=75388b165e68c977011d5047e6f20ab05de501f3;p=thirdparty%2Fautoconf.git

Document another make bug.

* doc/autoconf.texi (The Make Macro SHELL): Mention bug in BSD
make, GNU make <= 3.80.

Signed-off-by: Eric Blake <ebb9@byu.net>
---

diff --git a/ChangeLog b/ChangeLog
index 9b396f91f..772a4e3de 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2008-08-21  Eric Blake  <ebb9@byu.net>
 
+	Document another make bug.
+	* doc/autoconf.texi (The Make Macro SHELL): Mention bug in BSD
+	make, GNU make <= 3.80.
+
 	Tweak wording about SHELL in Makefile.
 	* doc/autoconf.texi (The Make Macro SHELL): Stronger wording on
 	the importance of proper SHELL settings.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 5e5c1ae6b..907bb83a9 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -16368,6 +16368,23 @@ $ @kbd{env SHELL=/bin/tcsh FOO=bar gmake -e}  # GNU make
 bar
 @end example
 
+Conversely, @command{make} is not supposed to export any changes to the
+macro @code{SHELL} to child processes.  Again, many implementations
+break this rule:
+
+@example
+$ @kbd{cat Makefile}
+all:
+        @@echo $(SHELL)
+        @@printenv SHELL
+$ @kbd{env SHELL=sh make -e SHELL=/bin/ksh}   # BSD Make, GNU make 3.80
+/bin/ksh
+/bin/ksh
+$ @kbd{env SHELL=sh gmake -e SHELL=/bin/ksh}  # GNU make 3.81
+/bin/ksh
+sh
+@end example
+
 @node Comments in Make Rules
 @section Comments in Make Rules
 @cindex Comments in @file{Makefile} rules