Re: reduce forks during autoconf

[Bruno Haible]

Eric Blake wrote:
> | +   echo "  m4_ifval([${macro_prefix_arg}_LIBSOURCES_LIST], ["
> 
> This needs to be m4_ifset, not m4_ifval.  As written, you are checking
> that *_LIBSOURCES_LIST is not the empty string (it's not)

Oops. I actually want to use m4_ifval, not m4_ifset, because it's a simple
binary test, not forcing me to think about the distinction between undefined
and empty value. (I hate JavaScript, where undefined, null, and empty string
are 3 different values!)

This fixes it and is what I meant:

--- gnulib-tool.orig    2008-05-14 04:05:59.000000000 +0200
+++ gnulib-tool 2008-05-14 04:04:02.000000000 +0200
@@ -2067,7 +2067,7 @@
   # The check is performed only when autoconf is run from the directory where
   # the configure.ac resides; if it is run from a different directory, the
   # check is skipped.
-  echo "  m4_ifval([${macro_prefix_arg}_LIBSOURCES_LIST], ["
+  echo "  m4_ifval(${macro_prefix_arg}_LIBSOURCES_LIST, ["
   echo "    m4_syscmd([test ! -d ]${macro_prefix_arg}_LIBSOURCES_DIR[ ||"
   echo "      for gl_file in ]${macro_prefix_arg}_LIBSOURCES_LIST[ ; do"
   echo "        if test ! -r ]${macro_prefix_arg}_LIBSOURCES_DIR[/\$gl_file ; 
then"