--- a/gecode.m4
+++ b/gecode.m4
@@ -38,7 +38,7 @@
 
 AC_DEFUN([AC_GECODE_GET_OS],
     [AC_ARG_WITH([host-os],
-           AC_HELP_STRING([--with-host-os],
+           AS_HELP_STRING([--with-host-os],
        [Override operating system test. Valid values are Linux, Darwin, FreeBSD, NetBSD, and Windows.]))
      AC_MSG_CHECKING([for the host operating system])
          if test "${with_host_os:-no}" = "no"; then
@@ -243,7 +243,7 @@
 
 AC_DEFUN([AC_CXX_COMPILER_VENDOR],
   [AC_ARG_WITH([compiler-vendor],
-     AC_HELP_STRING([--with-compiler-vendor],
+     AS_HELP_STRING([--with-compiler-vendor],
        [Override compiler test. Valid values are gnu, intel, and microsoft.]))
    AC_REQUIRE([AC_PROG_CXX])
    AC_REQUIRE([AC_PROG_CXXCPP])
@@ -334,7 +334,7 @@
    [AC_DEFINE(GECODE_HAS_$1_VARS, [], [Whether to build $1 variables])])
 AC_DEFUN([AC_GECODE_VIS],[
   AC_ARG_WITH([vis],
-    AC_HELP_STRING([--with-vis],
+    AS_HELP_STRING([--with-vis],
     [additional variable implementation specifications]))
     if test "${with_vis:-no}" != "no"; then
       with_vis=${with_vis//,/ }
@@ -343,7 +343,7 @@
 AC_DEFUN([AC_GECODE_VTI],
    [
    AC_ARG_ENABLE([$1-vars],
-     AC_HELP_STRING([--enable-$1-vars],[build $2 @<:@default=$3@:>@]))
+     AS_HELP_STRING([--enable-$1-vars],[build $2 @<:@default=$3@:>@]))
    ac_gecode_vis="$4${ac_gecode_vis:+ }${ac_gecode_vis}"
    AC_MSG_CHECKING(whether to build the $1 variables library)
    if test "${enable_$1_vars:-$3}" = "yes"; then
@@ -371,7 +371,7 @@
 AC_DEFUN([AC_GECODE_ENABLE_MODULE],
      [
      AC_ARG_ENABLE([$1],
-       AC_HELP_STRING([--enable-$1],
+       AS_HELP_STRING([--enable-$1],
          [$3 @<:@default=$2@:>@]))
      AC_MSG_CHECKING(whether to build $1)
      if test "${enable_$1:-$2}" = "yes"; then
@@ -393,7 +393,7 @@
 AC_DEFUN([AC_GECODE_ENABLE_CONTRIB],
 [
    AC_ARG_ENABLE([$1],
-     AC_HELP_STRING([--enable-$1],[build $2 @<:@default=yes@:>@]))
+     AS_HELP_STRING([--enable-$1],[build $2 @<:@default=yes@:>@]))
    AC_MSG_CHECKING(whether to build the $1 contrib library)
    if test "${enable_$1:-yes}" = "yes"; then
      AC_MSG_RESULT(yes)
@@ -413,7 +413,7 @@
         enable_shared="no"
       fi
       AC_ARG_ENABLE([static],
-        AC_HELP_STRING([--enable-static],
+        AS_HELP_STRING([--enable-static],
           [build static libraries @<:@default=no@:>@]))
       AC_MSG_CHECKING(whether to build static libraries)
         if test "${enable_static:-no}" = "yes"; then
@@ -428,7 +428,7 @@
           AC_MSG_RESULT(no)
         fi
       AC_ARG_ENABLE([shared],
-        AC_HELP_STRING([--enable-shared],
+        AS_HELP_STRING([--enable-shared],
           [build shared libraries @<:@default=yes@:>@]))
       AC_MSG_CHECKING(whether to build shared libraries)
         if test "${enable_shared:-yes}" = "yes"; then
@@ -445,7 +445,7 @@
 
 AC_DEFUN([AC_GECODE_CODESIZE],
     [AC_ARG_ENABLE([small-codesize],
-       AC_HELP_STRING([--enable-small-codesize],
+       AS_HELP_STRING([--enable-small-codesize],
          [optimize for code size @<:@default=no@:>@]))
      AC_MSG_CHECKING(whether to optimize for code size)
      if test "${enable_debug:-no}" = "yes"; then
@@ -469,7 +469,7 @@
 
 AC_DEFUN([AC_GECODE_DEBUG],
     [AC_ARG_ENABLE([debug],
-       AC_HELP_STRING([--enable-debug],
+       AS_HELP_STRING([--enable-debug],
          [build with assertions @<:@default=no@:>@]))
      AC_MSG_CHECKING(whether to build with debug symbols and assertions)
      if test "${enable_debug:-no}" = "yes"; then
@@ -485,7 +485,7 @@
 
 AC_DEFUN([AC_GECODE_LEAK_DEBUG],
     [AC_ARG_ENABLE([leak-debug],
-       AC_HELP_STRING([--enable-leak-debug],
+       AS_HELP_STRING([--enable-leak-debug],
          [build with support for finding memory leaks @<:@default=no@:>@]))
      AC_MSG_CHECKING(whether to build with support for finding memory leaks)
      if test "${enable_leak_debug:-no}" = "yes"; then
@@ -501,7 +501,7 @@
 
 AC_DEFUN([AC_GECODE_PEAKHEAP],
     [AC_ARG_ENABLE([peakheap],
-       AC_HELP_STRING([--enable-peakheap],
+       AS_HELP_STRING([--enable-peakheap],
          [build with peak heap size tracking @<:@default=no@:>@]))
      if test "${enable_peakheap:-no}" = "yes"; then
         AC_CHECK_FUNC(_msize,
@@ -558,7 +558,7 @@
 
 AC_DEFUN([AC_GECODE_ALLOCATOR],
     [AC_ARG_ENABLE([allocator],
-       AC_HELP_STRING([--enable-allocator],
+       AS_HELP_STRING([--enable-allocator],
          [build with default memory allocator @<:@default=yes@:>@]))
      AC_MSG_CHECKING(whether to build with default memory allocator)
      if test "${enable_allocator:-yes}" = "yes"; then
@@ -572,7 +572,7 @@
 
 AC_DEFUN([AC_GECODE_AUDIT],
     [AC_ARG_ENABLE([audit],
-       AC_HELP_STRING([--enable-audit],
+       AS_HELP_STRING([--enable-audit],
          [build with auditing code @<:@default=no@:>@]))
      AC_MSG_CHECKING(whether to build with auditing code)
      if test "${enable_audit:-no}" = "yes"; then
@@ -586,7 +586,7 @@
 
 AC_DEFUN([AC_GECODE_PROFILE],
      [AC_ARG_ENABLE([profile],
-       AC_HELP_STRING([--enable-profile],
+       AS_HELP_STRING([--enable-profile],
          [build with profiling information @<:@default=no@:>@]))
      AC_MSG_CHECKING(whether to build with profiling information)
      if test "${enable_profile:-no}" = "yes"; then
@@ -600,7 +600,7 @@
 
 AC_DEFUN([AC_GECODE_GCOV],
      [AC_ARG_ENABLE([gcov],
-       AC_HELP_STRING([--enable-gcov],
+       AS_HELP_STRING([--enable-gcov],
          [build with gcov support @<:@default=no@:>@]))
      AC_MSG_CHECKING(whether to build with gcov support)
      if test "${enable_gcov:-no}" = "yes"; then
@@ -755,7 +755,7 @@
 
 AC_DEFUN([AC_GECODE_GCC_VISIBILITY],
       [AC_ARG_ENABLE([gcc-visibility],
-       AC_HELP_STRING([--enable-gcc-visibility],
+       AS_HELP_STRING([--enable-gcc-visibility],
          [use gcc visibility attributes @<:@default=yes@:>@]))
      AC_MSG_CHECKING(whether to use gcc visibility attributes)
      if test "${enable_gcc_visibility:-yes}" = "yes"; then
@@ -940,7 +940,7 @@
 AC_DEFUN([AC_GECODE_DOC_SWITCHES],
   [dnl check if we can use dot for generating graphs in the documentation
    AC_ARG_ENABLE([doc-dot],
-     AC_HELP_STRING([--enable-doc-dot],
+     AS_HELP_STRING([--enable-doc-dot],
     [enable graphs in documentation @<:@default=yes@:>@]))
    AC_CHECK_PROG(DOT, dot, dot)
    AC_MSG_CHECKING(whether to enable graphs in the documentation)
@@ -962,7 +962,7 @@
    fi
 
    AC_ARG_ENABLE([doc-search],
-     AC_HELP_STRING([--enable-doc-search],
+     AS_HELP_STRING([--enable-doc-search],
     [enable documentation search engine @<:@default=no@:>@]))
    AC_MSG_CHECKING(whether to enable the documentation search engine)
    if test "${enable_doc_search:-no}" = "yes"; then
@@ -973,7 +973,7 @@
      AC_SUBST(ENABLEDOCSEARCH, "no")
    fi
    AC_ARG_ENABLE([doc-tagfile],
-     AC_HELP_STRING([--enable-doc-tagfile],
+     AS_HELP_STRING([--enable-doc-tagfile],
     [generate doxygen tagfile @<:@default=yes@:>@]))
    AC_MSG_CHECKING(whether to generate a doxygen tagfile)
    if test "${enable_doc_tagfile:-yes}" = "yes"; then
@@ -984,7 +984,7 @@
      AC_SUBST(GECODE_DOXYGEN_TAGFILE, [])
    fi
    AC_ARG_ENABLE([doc-chm],
-     AC_HELP_STRING([--enable-doc-chm],
+     AS_HELP_STRING([--enable-doc-chm],
     [build compressed html documentation @<:@default=yes on Windows@:>@]))
    AC_MSG_CHECKING(whether to build compressed html documentation)
    case $host_os in
@@ -1008,7 +1008,7 @@
     ;;
    esac
    AC_ARG_ENABLE([doc-docset],
-     AC_HELP_STRING([--enable-doc-docset],
+     AS_HELP_STRING([--enable-doc-docset],
     [build docset documentation for XCode @<:@default=no@:>@]))
    AC_MSG_CHECKING(whether to build docset documentation for XCode)
    case $host_os in
@@ -1045,7 +1045,7 @@
 AC_DEFUN([AC_GECODE_UNIVERSAL],
   [dnl build universal binaries on Mac OS X
   AC_ARG_WITH([sdk],
-    AC_HELP_STRING([--with-sdk],
+    AS_HELP_STRING([--with-sdk],
     [SDK to use on Mac OS X]))
   if test "${host_os}" = "darwin"; then
     if test "${with_sdk:-no}" != "no"; then
@@ -1054,7 +1054,7 @@
     fi
   fi
   AC_ARG_WITH([macosx-version-min],
-    AC_HELP_STRING([--with-macosx-version-min],
+    AS_HELP_STRING([--with-macosx-version-min],
     [minimum version of Mac OS X to support]))
   if test "${host_os}" = "darwin"; then
     if test "${with_macosx_version_min:-no}" != "no"; then
@@ -1065,7 +1065,7 @@
     fi
   fi
   AC_ARG_WITH([architectures],
-    AC_HELP_STRING([--with-architectures],
+    AS_HELP_STRING([--with-architectures],
     [architectures to compile for on Mac OS X]))
   AC_MSG_CHECKING(Whether to build for different architectures)
   if test "${host_os}" = "darwin"; then
@@ -1097,7 +1097,7 @@
 AC_DEFUN([AC_GECODE_FRAMEWORK],
   [dnl build framework bundle on Mac OS X
   AC_ARG_ENABLE([framework],
-    AC_HELP_STRING([--enable-framework],
+    AS_HELP_STRING([--enable-framework],
     [build framework bundle on Mac OS X @<:@default=no@:>@]))
   if test "${host_os}" = "darwin"; then
     AC_MSG_CHECKING(whether to build framework bundle on Mac OS X)
@@ -1123,7 +1123,7 @@
 AC_DEFUN([AC_GECODE_MPFR_INCLUDE],
   [dnl build with support for the mpfr header
   AC_ARG_WITH([mpfr-include],
-    AC_HELP_STRING([--with-mpfr-include],
+    AS_HELP_STRING([--with-mpfr-include],
     [path to the mpfr header file]))
   if test "${with_mpfr_include:-no}" != "no"; then
       AC_SUBST(MPFR_CPPFLAGS,[-I${with_mpfr_include}])
@@ -1140,7 +1140,7 @@
 AC_DEFUN([AC_GECODE_MPFR_LIB],
   [dnl build with support for the mpfr library
   AC_ARG_WITH([mpfr-lib],
-    AC_HELP_STRING([--with-mpfr-lib],
+    AS_HELP_STRING([--with-mpfr-lib],
     [path to the mpfr library]))
   if test "${with_mpfr_lib:-no}" != "no"; then
       case $ac_gecode_compiler_vendor in
@@ -1174,7 +1174,7 @@
 AC_DEFUN([AC_GECODE_GMP_INCLUDE],
   [dnl build with support for the gmp headers
   AC_ARG_WITH([gmp-include],
-    AC_HELP_STRING([--with-gmp-include],
+    AS_HELP_STRING([--with-gmp-include],
     [path to the gmp or mpir header files]))
   if test "${with_gmp_include:-no}" != "no"; then
       AC_SUBST(GMP_CPPFLAGS,[-I${with_gmp_include}])
@@ -1191,7 +1191,7 @@
 AC_DEFUN([AC_GECODE_GMP_LIB],
   [dnl build with support for the GMP library
   AC_ARG_WITH([gmp-lib],
-    AC_HELP_STRING([--with-gmp-lib],
+    AS_HELP_STRING([--with-gmp-lib],
     [path to the gmp or mpir library]))
 
   ac_gecode_tmp_gmp_lib=""
@@ -1256,7 +1256,7 @@
 AC_DEFUN([AC_GECODE_MPFR],
   [
   AC_ARG_ENABLE([mpfr],
-    AC_HELP_STRING([--enable-mpfr],
+    AS_HELP_STRING([--enable-mpfr],
       [build with MPFR support @<:@default=yes@:>@]))
   if test "${enable_float_vars:-yes}" = "yes"; then
     AC_MSG_CHECKING(whether to build with MPFR support)
@@ -1319,7 +1319,7 @@
 AC_DEFUN([AC_GECODE_QT],
   [
   AC_ARG_ENABLE([qt],
-    AC_HELP_STRING([--enable-qt],
+    AS_HELP_STRING([--enable-qt],
       [build with Qt support, requires at least Qt 4.3 @<:@default=yes@:>@]))
   AC_CHECK_PROGS(QMAKE, [qmake-qt4 qmake])
   AC_CHECK_PROGS(MOC, [moc-qt4 moc])
@@ -1397,7 +1397,7 @@
 AC_DEFUN([AC_GECODE_GIST],
   [
   AC_ARG_ENABLE([gist],
-    AC_HELP_STRING([--enable-gist],
+    AS_HELP_STRING([--enable-gist],
       [build Gecode Interactive Search Tool @<:@default=yes@:>@]))
   AC_MSG_CHECKING(whether to build Gist)
   if test "${enable_gist:-yes}" = "yes" -a "${enable_qt}" = "yes"; then
@@ -1422,7 +1422,7 @@
 AC_DEFUN([AC_GECODE_CBS],
   [
   AC_ARG_ENABLE([cbs],
-    AC_HELP_STRING([--enable-cbs],
+    AS_HELP_STRING([--enable-cbs],
       [build with support for counting-based search @<:@default=no@:>@]))
   AC_MSG_CHECKING(whether to build with support for cbs)
   if test "${enable_cbs:-no}" = "yes"; then
@@ -1447,7 +1447,7 @@
 AC_DEFUN([AC_GECODE_CPPROFILER],
   [
   AC_ARG_ENABLE([cpprofiler],
-    AC_HELP_STRING([--enable-cpprofiler],
+    AS_HELP_STRING([--enable-cpprofiler],
       [build with support for CPProfiler @<:@default=yes@:>@]))
   AC_MSG_CHECKING(whether to build with support for CPProfiler)
   if test "${enable_cpprofiler:-no}" = "yes"; then
@@ -1462,7 +1462,7 @@
 AC_DEFUN([AC_GECODE_USER_SUFFIX],
   [
   AC_ARG_WITH([lib-prefix],
-    AC_HELP_STRING([--with-lib-prefix],
+    AS_HELP_STRING([--with-lib-prefix],
       [add user-defined prefix to library names]))
   AC_MSG_CHECKING(for user-defined library name prefix)
   if test "x${with_lib_prefix}" != "x"; then
@@ -1475,7 +1475,7 @@
   AC_DEFINE_UNQUOTED(GECODE_DLL_USERPREFIX,"${ac_gecode_userprefix}",
     [User-defined prefix of dll names])
   AC_ARG_WITH([lib-suffix],
-    AC_HELP_STRING([--with-lib-suffix],
+    AS_HELP_STRING([--with-lib-suffix],
       [add user-defined suffix to library names]))
   AC_MSG_CHECKING(for user-defined library name suffix)
   if test "x${with_lib_suffix}" != "x"; then
@@ -1493,7 +1493,7 @@
 
 AC_DEFUN([AC_GECODE_THREADS],[
   AC_ARG_ENABLE([thread],
-    AC_HELP_STRING([--enable-thread],
+    AS_HELP_STRING([--enable-thread],
       [build with multi-threading support @<:@default=yes@:>@]))
   AC_MSG_CHECKING(whether to build with multi-threading support)
   if test "${enable_thread:-yes}" = "yes"; then
@@ -1555,7 +1555,7 @@
 
 AC_DEFUN([AC_GECODE_RESOURCE],[
   AC_ARG_ENABLE([resource],
-    AC_HELP_STRING([--enable-resource],
+    AS_HELP_STRING([--enable-resource],
       [build Gecode with resource files for Microsoft Visual Studio @<:@default=no@:>@]))
   AC_CHECK_PROG(HAVE_RC, rc.exe, [found])
   AC_MSG_CHECKING(whether to build with Visual Studio resource files)
