bashism in configure script

Theoretically the ./configure script is a pure bourne-shell script.
Practically it may be run by bash if /bin/sh is not good enough. But we should not count on it. See bug report for the gory details.

(closes issue #17485)
Patches:
      0001-remove-bashism-from-ast_check_pwlib.m4.patch uploaded by tzafrir (license 46)


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@270184 f38db490-d61c-443f-a65b-d21fe96a405b

autoconf/ast_check_pwlib.m4

@@ -202,8 +202,8 @@ AC_DEFUN([AST_CHECK_PWLIB_VERSION], [
 		$2_MAJOR_VERSION=`echo ${$2_VERSION} | cut -f1 -d.`
 		$2_MINOR_VERSION=`echo ${$2_VERSION} | cut -f2 -d.`
 		$2_BUILD_NUMBER=`echo ${$2_VERSION} | cut -f3 -d.`
-		let $2_VER=${$2_MAJOR_VERSION}*10000+${$2_MINOR_VERSION}*100+${$2_BUILD_NUMBER}
-		let $2_REQ=$4*10000+$5*100+$6
+		$2_VER=$((${$2_MAJOR_VERSION}*10000+${$2_MINOR_VERSION}*100+${$2_BUILD_NUMBER}))
+		$2_REQ=$(($4*10000+$5*100+$6))
 
 		AC_MSG_CHECKING(if $1 version ${$2_VERSION} is compatible with chan_h323)
 		if test ${$2_VER} -lt ${$2_REQ}; then