Hi,
The configure script of autoconf 2.64/2.65/HEAD fails to detect a
suitable m4 on my system. It aborts with
autoconf-2.65 0 $ ./configure
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking whether /bin/sh -n is known to work... no
checking for characters that cannot appear in file names... none
checking whether directories can have trailing spaces... yes
checking for expr... /usr/bin/expr
checking for GNU M4 that supports accurate traces... configure: error:
no acceptable m4 could be found in $PATH.
GNU M4 1.4.6 or later is required; 1.4.13 is recommended
I have GNU M4 1.4.13. The problem is that I'm using dash for /bin/sh
(and my dash supports LINENO so configure doesn't silently use bash
instead), and the m4 detection doesn't work when echo \1 prints ^A.
With the attached obvious patch, configure passes, and there's no
problem further on.
diff --git a/m4/m4.m4 b/m4/m4.m4
index 096fb28..be86031 100644
--- a/m4/m4.m4
+++ b/m4/m4.m4
@@ -29,7 +29,7 @@ AC_PATH_PROGS_FEATURE_CHECK([M4], [m4 gm4 gnum4],
ac_snippet=change'quote(<,>)in''dir(<if''def>,mac,bug)'
ac_snippet=${ac_snippet}pat'subst(a,\(b\)\|\(a\),\1)d'nl
test -z "`$ac_path_M4 -F conftest.m4f </dev/null 2>&1`" \
- && test -z "`echo $ac_snippet | $ac_path_M4 --trace=mac 2>&1`" \
+ && test -z "`AS_ECHO([$ac_snippet]) | $ac_path_M4 --trace=mac 2>&1`" \
&& test -f conftest.m4f \
&& ac_cv_path_M4=$ac_path_M4 ac_path_M4_found=:
rm -f conftest.m4f],
