[PATCH 0/2] ocaml: Start on fixing brokenness when no ocamlopt

[Ian Jackson <ian.jackson@eu.citrix.com>]

Debian jessie arm64 has Ocaml (in the package `ocaml-nox') but the
package lacks ocamlopt.

This causes xen.git builds to fail.  Our configure script detects that
ocaml is available.  Our version of m4/ocaml.m4 sort of tries to
figure out what the best compiler is but only does have the job.  And
then our tools/ocaml/common.make unconditionally uses ocamlopt.

I am not sure exactly how to fix this (see below) but I think these
two patches are an essential start:

 1/2  ocaml: Copy up-to-date m4/ocaml.m4 from forge.ocamlcore
 2/2  ocaml: Substitute tools/ocaml/common.make with configure

(An alternative for 1/2 would be a git merge, which would provide the
docs and git history and so on - but the ocaml-autoconf README seems
to expetus to copy the m4 into our own project.)

This does not actually fix the real problem.  I'm unsure how to fix it
properly, for the following reasons:

ocaml.m4 expects to set OCAMLC to either `ocamlopt' or failing that
`ocamlc'.  However our ocaml Makefiles seem to explicitly call
$(OCAMLOPT) in some places and and $(OCAMLC) in others.

Simply changing tools/ocaml/common.make to substitute the variables
from their corresponding autoconf names seems like it isn't right.

Our Makefiles explicitly call ocamlc via OCAMLC right now even when
ocamlopt is available, and substituting OCAML would change those calls
to OCAMLOPT.  And it wouldn't help fix the actual build failure,
either, because if there is no ocamlopt, the m4 doesn't provide a
useful OCAMLOPT.

FYI the ocamlforge m4 comes with a pod.  You can get it from
  https://forge.ocamlcore.org/anonscm/git/ocaml-autoconf/ocaml-autoconf.git

I haven't copied that into xen.git in patch 1/2.  Should I ?
In the meantime, a formatted copy is below.

Ian.




IO::FILE=IO(0X834C450)User Contributed Perl DocumentaIO::FILE=IO(0X834C450)(1)



NAME
       ocaml.m4 - Autoconf macros for OCaml

SUMMARY
        AC_PROG_OCAML
        AC_PROG_FINDLIB
        AC_PROG_OCAMLLEX
        AC_PROG_OCAMLYACC
        AC_PROG_CAMLP4
        AC_CHECK_OCAML_PKG([name])
        AC_CHECK_OCAML_MODULE(VARIABLE,NAME,MODULE,INCLUDE-PATHS)
        AC_CHECK_OCAML_WORD_SIZE

DESCRIPTION
       ocaml.m4 is a file containing standard, useful autoconf macros for
       detecting the OCaml, findlib, OCaml packages, and so on in your
       autoconf-generated ./configure scripts.

       To begin using these macros, you will need to copy the "ocaml.m4" file
       (usually located at "/usr/share/aclocal/ocaml.m4") to the autoconf
       macros directory in your project.  Normally this is the "m4/" directory
       in your project, but the directory can be changed using the
       "AC_CONFIG_MACRO_DIR(DIR)" directive.  If you have just created the
       "m4/" directory, then you may also need to do:

        aclocal -I m4

       You can then add any of the macros described below to your
       "configure.ac" (or "configure.in"). Almost every OCaml project should
       use "AC_PROG_OCAML" first and probably "AC_PROG_FINDLIB" right after
       it.

       This manual page does not describe how to use autoconf.  For that you
       should read the detailed autoconf info file ("info autoconf").

AC_PROG_OCAML
       This macro detects which tools of the usual OCaml toolchain are
       available. It defines and substitutes the following variables:

        OCAMLC          set to the name of the bytecode compiler
                          (eg. "ocamlc" or "ocamlc.opt"), or "no" if
                          no OCaml installation was found
        OCAMLOPT        the name of the native-code compiler, eg. "ocamlopt",
                          "ocamlopt.opt" or "no"
        OCAMLBEST       "byte" (if only the bytecode compiler is available)
                          or "opt" (if both bytecode and native code compilers
                          are available)
        OCAMLNATDYNLINK "yes" (if native dynlink is available) or "no"
        OCAMLDEP        the name of the dependency resolver, eg. "ocamldep"
        OCAMLMKTOP      the name of ocamlmktop
        OCAMLMKLIB      the name of ocamlmklib
        OCAMLDOC        the name of ocamldoc
        OCAMLBUILD      the name of ocamlbuild
        OCAMLLIB        the OCaml library path (eg. C</usr/lib/ocaml/>)
        OCAMLVERSION    the compiler version (eg. C<3.11.0>)

   Detecting if OCaml is installed
       Unlike old versions of these macros, "AC_PROG_OCAML" does not exit if
       no OCaml installation is detected.  Therefore if you want to detect if
       OCaml is installed you have to do something like this:

        AC_PROG_OCAML
        if test "$OCAMLC" = "no"; then
          AC_MSG_ERROR([You must install the OCaml compiler])
        fi

       This behaviour and usage pattern are consistent with other macros of
       the "AC_PROG_*") family.

   Cross-compiling
       If the configure script is invoked for cross-compiling then
       "AC_PROG_OCAML" will detect the cross-compiler versions of the OCaml
       compiler, eg. "OCAMLC=i686-pc-mingw32-ocamlc" etc.  This happens
       automatically, and for most purposes you don't need to worry about it.

AC_PROG_FINDLIB
       This macro checks for the presence of the ocamlfind program (part of
       findlib).  It defines and substitutes "OCAMLFIND" to the name of the
       ocamlfind program, or "no" if not found.

       Note that this macro does not fail if ocamlfind is not found.  If you
       want to force the user to install findlib, you should do:

        AC_PROG_FINDLIB
        if test "$OCAMLFIND" = "no"; then
          AC_MSG_ERROR([You must install OCaml findlib (the ocamlfind command)])
        fi

       See also "AC_CHECK_OCAML_PKG".

AC_PROG_OCAMLLEX
       This checks for the ocamllex program and sets "OCAMLLEX" to the name of
       the program (eg. "ocamllex" or "ocamllex.opt"), or "no" if not found.

AC_PROG_OCAMLYACC
       This checks for the ocamlyacc program and sets "OCAMLYACC" to the name
       of the program, or "no" if not found.

AC_PROG_CAMLP4
       This checks for camlp4, and checks that the version matches the
       compiler version found previously.  It sets "CAMLP4" to the name of the
       basic camlp4 program, or "no" if not found.

       The macro also checks for other tools of the camlp4 suite like camlp4o,
       camlp4orf, etc. For each of them, a fully capitalized variable is set
       to the tool name (or "no" if not found); all variable are substituted
       for when filling .in files. The full list of tools and respective
       variable names is as follows:

        camlp4        CAMLP4
        camlp4boot    CAMLP4BOOT
        camlp4o       CAMLP4O
        camlp4of      CAMLP4OF
        camlp4oof     CAMLP4OOF
        camlp4orf     CAMLP4ORF
        camlp4prof    CAMLP4PROF
        camlp4r       CAMLP4R
        camlp4rf      CAMLP4RF

AC_CHECK_OCAML_PKG
       This is the main macro that can be used to detect the presence of OCaml
       findlib packages.  This macro uses ocamlfind to look up findlib
       packages (and thus requires that findlib itself has been installed, and
       that the package has been properly packaged with a META file etc.)  If
       you want to find an OCaml findlib package which hasn't been installed
       with findlib then you should try using "AC_CHECK_OCAML_MODULE" instead.

        AC_CHECK_OCAML_PKG([name])

       checks for an OCaml findlib package with the given name. If found, it
       defines and substitutes the variable "OCAML_PKG_name" where the "name"
       part is substituted for the package name by replacing all dashes with
       underscores.

       For example,

        AC_CHECK_OCAML_PKG([xml-light])

       will set "OCAML_PKG_xml_light" to either "xml-light" or "no".

       To have the configure script fail if a package is not installed, do:

        AC_CHECK_OCAML_PKG([foo])
        if test "$OCAML_PKG_foo" = "no"; then
          AC_MSG_ERROR([Please install OCaml findlib module 'foo'.])
        fi

       In your Makefile.in, use the substitution variable in conjunction with
       ocamlfind, eg:

        .ml.cmo:
          $(OCAMLFIND) ocamlc -package @OCAML_PKG_foo@ -c $< -o $@

       Note that also in the substitution variable dashes are replaced with
       underscores.

   Checking for alternative findlib package names
       In the (unlikely) case where the same library corresponds to different
       findlib package names on different systems, you can improve portability
       by checking for the alternative names passing a second argument to
       "AC_CHECK_OCAML_PKG":

        AC_CHECK_OCAML_PKG(PKGNAME,ALTERNATIVE-NAMES)

       The behaviour is the same as before if "PKGNAME" is found. Otherwise
       all names in "ALTERNATIVE-NAMES" are tested in turn as findlib package
       names. If one is found, it is set as the value set by the macro and
       substituted in .in files; otherwise "no" is set.

       Note that the variable name is determined by "PKGNAME", while the value
       depends on the actual alternative name found.

       For example, to detect the camlzip findlib package, either called "zip"
       or "camlzip", and to store the found value in the "OCAML_PKG_zip"
       variable you can do in your configure.ac:

        AC_CHECK_OCAML_PKG(zip,camlzip)

       and have a portable Makefile.in build line such as:

        .ml.cmo:
          $(OCAMLFIND) ocamlc -package @OCAML_PKG_zip@ -c $< -o $@

AC_CHECK_OCAML_MODULE(VARIABLE,NAME,MODULE,INCLUDE-PATHS)
       "AC_CHECK_OCAML_MODULE" is the hairier alternative to
       "AC_CHECK_OCAML_PKG".  You should always use "AC_CHECK_OCAML_PKG" and
       ocamlfind/findlib if possible.

       The parameters are:

       VARIABLE
           This is the environment variable that is set.  It will either be
           set to the include path, or to "no" if the module was not found.

       NAME
           This is the name of the module we are looking for.  This parameter
           is just used for printing messages, and does not affect how the
           module is found.

       MODULE
           This should be an OCaml module name, representing the module name
           being looked up.  You can put sub-modules here, eg.
           "CalendarLib.Date"

       INCLUDE-PATHS
           This is the default list of include directories to search, eg.
           "+calendar"

       For example, the following code will check for the OCaml Calendar
       module, and will distinguish between version 1 and version 2 of this
       module (which have incompatible APIs).

        AC_CHECK_OCAML_PKG(calendar)
        AC_CHECK_OCAML_MODULE(is_calendar2,calendar,[CalendarLib.Date],[+calendar])

       After the above code has run, variables "OCAML_PKG_calendar" and
       "is_calendar2" will be set as follows:

        OCAML_PKG_calendar  is_calendar2  Result

        yes                 +calendar     Calendar v2 is installed
        yes                 no            Calendar v1 is installed
        no                  no            No Calendar module installed

AC_CHECK_OCAML_WORD_SIZE
       This checks the word size of the OCaml compiler, and sets
       "OCAML_WORD_SIZE" to either 32 or 64.

SEE ALSO
       autoconf(1), <http://ocaml-autoconf.forge.ocamlcore.org>,
       <http://caml.inria.fr/>

FILES
       ·   /usr/share/aclocal/ocaml.m4

AUTHORS
       Various people have contributed to these macros over many years:

       ·   Olivier Andrieu

       ·   Jean-Christophe Filliatre

       ·   Richard W.M. Jones

       ·   Georges Mariano

       ·   Jim Meyering

       ·   Stefano Zacchiroli

LICENSE
        Copyright X 2009      Richard W.M. Jones
        Copyright X 2009      Stefano Zacchiroli
        Copyright X 2000-2005 Olivier Andrieu
        Copyright X 2000-2005 Jean-Christophe Filliatre
        Copyright X 2000-2005 Georges Mariano

        All rights reserved.

        Redistribution and use in source and binary forms, with or without modification,
        are permitted provided that the following conditions are met:

        * Redistributions of source code must retain the above copyright notice, this
        list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above copyright notice,
        this list of conditions and the following disclaimer in the documentation
        and/or other materials provided with the distribution.
        * The names of the contributors may not be used to endorse or promote
        products derived from this software without specific prior written
        permission.

        THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
        EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
        WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
        DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
        DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
        (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
        LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
        ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
        (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
        SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

REPORTING BUGS
       Please report bugs to the authors at the project page:
       <http://forge.ocamlcore.org/projects/ocaml-autoconf/>, using the forge
       bug tracker <http://forge.ocamlcore.org/tracker/?group_id=69>.



perl v5.20.2                      2017-01-20         IO::FILE=IO(0X834C450)(1)

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