bugfix in AX_PKG_REQUIRE

ax_init_standard_project.m4

@@ -68,7 +68,7 @@ dnl refers to ${prefix}.  Thus we have to use `eval' twice.
 #     $3 = filename of makefile.in
 AC_DEFUN([AX_ADD_MAKEFILE_TARGET_DEP], [
   sh_add_makefile_target_dep() {
-    sed -i ':a;/^'${1}':.*\\$/{N;s/\\\n//;ta};s/^'${1}':.*$/& '${2}'/' "${srcdir}/${3}"
+    sed -i -e ':a;/^'${1}':.*\\$/{N;s/\\\n//;ta};s/^'${1}':.*$/& '${2}'/' "${srcdir}/${3}"
     if ! egrep -q "${1}:.* ${2}" "${srcdir}/${3}"; then
         echo "${1}: ${2}" >> "${srcdir}/${3}"
     fi