Re: [bug #31646] grep fails to build on Solaris 10, because it lacks grep

[Paolo Bonzini]

On 11/14/2010 03:09 PM, Jim Meyering wrote:
>> It is possible to disable the body of these two expansions by
>> assigning values to GREP and EGREP inside the configure script.
> 
> But with no grep program already installed, that will always fail.

You can implement a basic grep that is "good enough for configure"
using while/read and case.  You will use the newly-built grep
after it's, well, built.  But nobody uses grep in "make all", so
it can be substituted unconditionally in Makefiles, and a shell
function can replace the dummygrep binary.

This is the patch:

2010-11-14  Paolo Bonzini  <address@hidden>

        * configure.ac (fn_grep): New.  Set GREP and EGREP to it,
        replace with newly-built grep before AC_OUTPUT.

diff --git a/configure.ac b/configure.ac
index 481ce86..87a38cc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,6 +22,36 @@ AC_INIT([GNU grep],
         m4_esyscmd([build-aux/git-version-gen .tarball-version]),
         address@hidden)
 
+# Override grep during configure.
+fn_grep () {
+  test $1 = -E && shift
+  case address@hidden:@:$1 in
+    0:*) AC_MSG_ERROR([fn_grep: expected pattern]) ;;
+    1:-*) AC_MSG_ERROR([fn_grep: invalid command line]) ;;
+    1:*) pattern=$1 ;;
+    2:--|2:-e|2:-Ee) pattern=$2 ;;
+    *) AC_MSG_ERROR([fn_grep: invalid command line]) ;;
+  esac
+
+  case $pattern in
+    *[].^$\\*[]*) AC_MSG_ERROR([fn_grep: regular expressions not supported])  
;;
+  esac
+
+  rc=1
+  while read line; do
+    case $line in
+      *$pattern*)
+        rc=0
+        AS_ECHO([$line]) ;;
+    esac
+  done
+  return $rc
+}
+
+test -n "$GREP" || GREP=fn_grep
+test -n "$EGREP" || EGREP=fn_grep
+ac_cv_path_EGREP=$EGREP
+
 AC_CONFIG_AUX_DIR(build-aux)
 AC_CONFIG_SRCDIR(src/grep.c)
 AC_DEFINE([GREP], 1, [We are building grep])
@@ -167,4 +197,6 @@ AC_CONFIG_FILES([
   doc/Makefile
   gnulib-tests/Makefile
 ])
+GREP="$ac_abs_top_builddir/src/grep"
+EGREP="$ac_abs_top_builddir/src/egrep"
 AC_OUTPUT