Basically, this commit only simplifies configure.ac and makes the

mechanism more flexible, but otherwise should not affect your build
even if you regenerate the "configure" script.
(Most likely you need to run bootstrap.sh as you really need to re-run
autoheader for reasons that i do not completely understand).

If you don't regenerate "configure", of course you will see no difference.

In detail:

- restructure the check for mandatory modules to remove some
  redundant code blocks;

- extend the AST_EXT_LIB_CHECK so that it can used also for
  checking headers;

- define the AST_C_DEFINE_CHECK macro to test for #defined symbols;

- for the two above macros, add a last argument that getscopied into
  HAVE_$1_VERSION so the source can adapt to different versions of the
  same libraries/header/etc

- document the above;

- document a problem that existed before and i did not manage to solve:
  the 'description' argument to AC_DEFINE does not substiture shell variables
  so you will not see the actual values in the comments (in autoconfig.h)..




git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@44467 65c4cc65-6c06-0410-ace0-fbb531ad65f3

acinclude.m4

@@ -23,11 +23,11 @@ case ${withval} in
      USE_$1=no
      ;;
      y|ye|yes)
-     $1_MANDATORY="yes"
+     ac_mandatory_list="${ac_mandatory_list} $1"
      ;;
      *)
      $1_DIR="${withval}"
-     $1_MANDATORY="yes"
+     ac_mandatory_list="${ac_mandatory_list} $1"
      ;;
 esac
 ])
@@ -37,14 +37,68 @@ AC_SUBST([$1_INCLUDE])
 AC_SUBST([PBX_$1])
 ])
 
-# Check for existence of a given package ($1), looking up a function
+# Check whether any of the mandatory modules are not present, and
+# print error messages in case.
+
+AC_DEFUN([AST_CHECK_MANDATORY],
+[
+	AC_MSG_CHECKING([for mandatory modules: ${ac_mandatory_list}])
+	err=0;
+	for i in ${ac_mandatory_list}; do
+		eval "a=\${PBX_$i}"
+		if test "x${a}" = "x1" ; then continue; fi
+		if test ${err} = "0" ; then AC_MSG_RESULT(fail) ; fi
+		AC_MSG_RESULT()
+		eval "a=\${${i}_OPTION}"
+		AC_MSG_NOTICE(***)
+		AC_MSG_NOTICE(*** The $i installation appears to be missing or broken.)
+		AC_MSG_NOTICE(*** Either correct the installation, or run configure)
+		AC_MSG_NOTICE(*** including --without-${a}.)
+		err=1
+	done
+	if test $err = 1 ; then exit 1; fi
+	AC_MSG_RESULT(ok)
+])
+
+#-- The following two tests are only performed if PBX_$1 != 1,
+#   so you can use multiple tests and stop at the first matching one.
+#   On success, set PBX_$1 = 1, and also #define HAVE_$1 1
+#   and #define HAVE_$1_VERSION ${last_argument} so you can tell which
+#   test succeeded.
+#   They should be called after AST_EXT_LIB_SETUP($1, ...)
+
+# Check if a given macro is defined in a certain header.
+
+# AST_C_DEFINE_CHECK([package symbol name], [macro name], [header file], [version])
+AC_DEFUN([AST_C_DEFINE_CHECK],
+[
+    if test "x${PBX_$1}" != "x1" -a "${USE_$1}" != "no"; then
+	AC_MSG_CHECKING([for $2 in $3])
+	saved_cppflags="${CPPFLAGS}"
+	if test "x${$1_DIR}" != "x"; then
+	    $1_INCLUDE= "-I${$1_DIR}/include"
+	fi
+	CPPFLAGS="${CPPFLAGS} ${$1_INCLUDE}"
+
+	AC_COMPILE_IFELSE(
+	    [ AC_LANG_PROGRAM( [#include <$3>], [int foo = $2;]) ],
+	    [   AC_MSG_RESULT(yes)
+		PBX_$1=1
+		AC_DEFINE([HAVE_$1], 1, [Define if your system has the $1 headers.])
+		AC_DEFINE([HAVE_$1_VERSION], $4, [Define $1 headers version])
+	    ],
+	    [       AC_MSG_RESULT(no) ] 
+	)
+	CPPFLAGS="${saved_cppflags}"
+    fi
+])
+
+
+# Check for existence of a given package ($1), either looking up a function
 # in a library, or, if no function is supplied, only check for the
 # existence of the header files.
-# Only check if PBX_$1 != 1, and set PBX_$1=1 and HAVE_$1 if found.
-# Should be called after AST_EXT_LIB_SETUP($1, ...)
-
-# AST_EXT_LIB_CHECK([package symbol name], [package library name], [function to check], [package header], [additional LIB data])
 
+# AST_EXT_LIB_CHECK([package symbol name], [package library name], [function to check], [package header], [additional LIB data], [version])
 AC_DEFUN([AST_EXT_LIB_CHECK],
 [
 if test "x${PBX_$1}" != "x1" -a "${USE_$1}" != "no"; then
@@ -78,13 +132,6 @@ if test "x${PBX_$1}" != "x1" -a "${USE_$1}" != "no"; then
 	 fi
       fi
       if test "x${$1_HEADER_FOUND}" = "x0" ; then
-         if test ! -z "${$1_MANDATORY}" ; then
-            AC_MSG_NOTICE( ***)
-            AC_MSG_NOTICE( *** It appears that you do not have the $2 development package installed.)
-            AC_MSG_NOTICE( *** Please install it to include ${$1_DESCRIP} support, or re-run configure)
-            AC_MSG_NOTICE( *** without explicitly specifying --with-${$1_OPTION})
-            exit 1
-         fi
          $1_LIB=""
          $1_INCLUDE=""
       else
@@ -92,14 +139,10 @@ if test "x${PBX_$1}" != "x1" -a "${USE_$1}" != "no"; then
 	    $1_LIB=""
 	 fi
          PBX_$1=1
-         AC_DEFINE_UNQUOTED([HAVE_$1], 1, [Define to indicate the ${$1_DESCRIP} library])
+         # XXX don't know how to evaluate the description (third argument) in AC_DEFINE_UNQUOTED
+         AC_DEFINE_UNQUOTED([HAVE_$1], 1, [Define this to indicate the ${$1_DESCRIP} library])
+	 AC_DEFINE_UNQUOTED([HAVE_$1_VERSION], [$6], [Define to indicate the ${$1_DESCRIP} library version])
       fi
-   elif test ! -z "${$1_MANDATORY}"; then
-      AC_MSG_NOTICE(***)
-      AC_MSG_NOTICE(*** The ${$1_DESCRIP} installation on this system appears to be broken.)
-      AC_MSG_NOTICE(*** Either correct the installation, or run configure)
-      AC_MSG_NOTICE(*** without explicitly specifying --with-${$1_OPTION})
-      exit 1
    fi
 fi
 ])