GNU Autoconf 2.12 for EMX

Current patchlevel: 5

Table of contents
Introduction
How it works
News in this release
Requirements for running
A simple instal from the binaries
A not so simple install from the sources
Using autoconf
Tips and tricks
Bug reports
Greetings and notes
Getting it

Introduction

Well I quite like OS/2 and spend much of my free time tweaking Linux programs to work with it. And sometimes I even get it!

What I've found that makes porting more difficult is sometimes building all those makefiles and configuration headers. Under Linux and most Unix like O.S. you would run a configure script that guesses most of your system peculiarities (Name of the C/C++ compiler, which headers and libraries are present, whether a function is broken...). But OS/2 is not Unix --nor even similar-- and there are enough differences to break up those configuration scripts, even if you already have a good sh-like shell.

OK, it was the state of the question until now. This port of Autoconf introduces a set of scripts and macro files able to build scripts that work well under OS/2 with EMX using all those wonderful ports of GNU utilities. But hey, that's not all. Now those scripts will work under unix as well!

How it works

Most Linux programs come with a configure script that has the purpose of guessing important system defaults. Currently, most of those scripts are built with a tool named Autoconf, from the FSF, which takes in one or two macro files (configure.in & aclocal.m4) and using the M4 macro processor and another internal set of macro files (mainly acgeneral.m4 & acspecific.m4) creates a third one, named configure. What I've done is tweaking the internal macro files, so that the code they produce is well suited to run under EMX with a filesystem that allows long file names. This release is a major rewriting of the port. The most important changes are listed in the following section.

News in this package

This version is not only a patch release. All of the previously introduced changes have been arranged in a way that make them GNU compliant and unix compatible. I expect this changes to become part of a new official release of Autoconf. Help me to get it!

New rules and macros to know the right format of a file name: now program, library and object files have the right extension and prefix both under OS/2 and Unix. The appropiate values for the current system are stored in the EXE_EXT, LIB_EXT, LIB_PRE, OBJ_EXT output variables. You can use them in Makefiles (see below).
Avoid looking for executable files in OS/2 & Window's directories (the reason for doing this is that the GNU install utility has the same name as the install program from OS/2 & Win).
New rules to know the PATH separator character: it's ":" in Unix and ";" in OS/2.
Instead of manipulating PATH, its value is saved, properly formatted, in FPATH (any "\" is translated to "/"). FPATH is used when searching for programs.
A new macro, AC_LOOP_OVER_PATH, is introduced. It repeats the same action over a list of path names (By default the FPATH one). It is designed in a way that hides all of the operating system features.
Some system specific defaults are arranged in a single macro, that can grow to support other operating systems, such as Win32 and DOS.
Changed all rules so that they undestand drive unit names.
Add rules for finding XFreeOS/2 under OS/2.
Added a #include <sys/types.h> line in every test, so that EMX doesn't issue all those warnings.
Added the --auxfiles option.

Requirements for running Autoconf

Here's a list of the EMX programs you'll need. Most of them are at Leo or Hobbes. However I've uploaded a few, standalone OS/2 binaries to my site: they're Kai's ports compiled without gnuregex.dll or gnurx.dll.

GNU file, text and shell utilitities.
GNU m4 1.4 macro processor.
GNU sed 2.05 and GNU grep 2.0.
Korn Shell 5.2.13 or newer --watch the number!!-- or Ash. If you use Ash, make sure you have the latest release (>= ash-0.2-4).
GNU awk 2.15-5.
GNU make. Make sure it is <= 3.72. You can also use XfreeOS/2 x11make.exe which is nothing but GNU Make 3.71, but never use make.cmd, the wrapper for x11make.exe.

And you must also be working on a filesystem that allows long file names. This happens under OS/2 with HPFS --and RSX+Win95/NT would do, too, but I haven't got any of them, so I could not test it--.

A simple install from the binaries

Make a directory for Autoconf and unpack the binary distribution package (autoconf*emxbin.zip) there. Let's say it is c:\apps\autoconf
Either add that directory to PATH or move the script files autoconf, autoreconf, autoheader, autoscan, autoupdate and ifnames to some other directory which *is* listed in PATH.
Define the AC_MACRODIR environment variable with the path to the place where you unpacked aconf*b.zip. For instance, if it was c:\apps\autoconf, add the following line to your config.sys:
```
	SET AC_MACRODIR=c:/apps/autoconf
```
Beware with slashes: you must use `/', not `\'.
You're free to move the documentation (*.info* files) to any place which is listed in INFOPATH.
You'll need AWKto run Autoconf, make sure you have an executable named `awk.exe' or set the AWK environment variable: for instance, in my system it would be
```
	set AWK=e:/usr/bin/gawk.exe
```

A not so simple install from the sources

Get in autoconf's directory.
Start an system shell and type "build --clean". This should remove configure config.cache config.status & config.log. (Note: autoconf's options are case sensitive, that is, use always lowercase for them) Alternatively, you can remove those files by hand.
Now simply type build and you'll get a configure file that is about 32Kbytes long.
Create a unix-like directory structure. My system has the following one
```
e:/usr
 +--->e:/usr/bin
 +--->e:/usr/info
 ...
 +--->e:/usr/local
       +--->e:/usr/local/bin
       +--->e:/usr/local/info
       ...
```
and e:/usr/bin and e:/usr/local/bin are in the PATH environment variable. When installing, Autoconf chooses the root directory you tell it (in my system it could be either e:/usr or e:/usr/local), builds several directories inside it and uses them to stores script, texinfo and macro files. Let's say `root' is e:/usr/local. Then
- e:/usr/local/bin should be in PATH
- e:/usr/local/bin is where scripts will be stored
- e:/usr/local/info is where the texinfo files will go
- e:/usr/local/share/autoconf is where the macro files will be
At the command prompt type something like
```
[From within CMD.EXE]
	sh configure --prefix=your_root_directory
[From within SH.EXE]
	configure --prefix=your_root_directory
```
where sh is the name of your unix-like shell. This will tipically find m4, awk --and perl.exe in case you have it-- and create customized makefiles for autoconf.
For example, in the system described above, I would use
```
	sh configure --prefix=e:/usr/local
```
Invoke GNU make. This builds the customized scripts autoconf, autoheader, autoreconf, autoupdate, and ifnames.
Note: You can either use make.exe, or even call x11make.exe if you have the XFreeOS/2 programmer's toolkit. But never use a simple make as the XFreeOS/2 make.cmd script could get in your way.
If everything went right, type
```
	make.exe install
```
and you'll have the scripts, the macro files and the info files installed.

Note: if you ever need to move autoconf to another directory, you'll have to either reinstall using this procedure, or define the environment variables listed in "Install from the binaries".

Using autoconf

Get in the directory which has the code you want to port.
The configure file must be already there: rename it to configure.bak.
Enter the unix shell. If you don't, you'll have to enclose the commands in double quoutes and prepend a `sh -c' to all of them. For example:
```
[From within CMD.EXE]
	sh -c "autoconf --clean"
[From within SH.EXE]
	autoconf --clean
```
Replace the config.sub, config.guess, mkinstalldirs & install-sh files by issuing the following command:
```
	autoconf --auxfiles
```
Remove the cache files:
```
	autoconf --clean
```
This should be done every time configure is rebuilt or after anything in your system changed (new programs installed, new PATH, etc) so that configure finds out those changes.
Build a brand new configure:
```
	autoconf
```
If you know your program is going to need some special flags, such as -Zmt, -D__ST_MT_ERRNO__, etc, then edit the lines in configure for CCFLAGS (C compiling flags), CXXFLAGS (C++ compiling flags), LDFLAGS (Flags for linking).
Alternatively, you can export environment variables before using configure overriding the checks it could do. See Tips and Tricks for more about this.
Run configure with any other options you wish. Usually
```
	configure --help
```
will inform you about the available options (programs to build, extensions, checks to avoid or include, etc), whereas
```
	configure --prefix=d:/usr
```
will configure using default options and defining the root directory to be /usr.
Watch the output: if the script can't find a program, library or file you DO have; or if some strange error comes out, please e-mail me but don't abuse the author. But first have a look at Tips and Bug reports.
Check all the files that have been updated (configure shows their names). They're usually makefiles and a config.h. If you see a path messed (i.e. /usr/../c:/usr/bin/sh.exe) and you cannot figure out why configure failed, tell me. But please first have a look at Tips and Bug reports.
Now do the real port: check the code and fix it. Here I cannot help you ;)

Tips and tricks

Drive unit names and extensions

Unix programs don't know about disk units names, such as 'C:'. I've made Autoconf understand drive unit names, but this doesn't mean that your program does.

In the configuration process Autoconf may introduce absolute pathnames in the code of your program. This will typically happen, either when config.h is created, or by explicit defines when compiling. You might have to add code to let the user override these paths.

OTOH, you might find hand-made rules in aclocal.m4 or in configure.in that check whether a path reference is absolute or not. Typically it looks like in this example:

...
case "$LD" in
  /*)	ac_program_LD="$LD";;
  *)	#some other stuff
...

This must be fixed in the following compatible mode:

...
case "$LD" in
  /* | [a-zA-Z]:*) ac_program_LD="$LD";;
  *)    #some other stuff
...

The fixed rule recognizes drive unit names. Also, as the colon ":" is not a valid path character under unix, it causes no big harm.

Compilation flags

Autoconf's default flags for compiling programs are, as of this release

	CC=gcc
	MAKE=make.exe
	CXX=gcc
	CPP="gcc.exe -E"
	CFLAGS="-O2 -Zmt"
	CXXFLAGS="-O2 -Zmt"
	LDFLAGS="-Zexe -Zmt -Zcrtdll -Zsysv-signals -Zbin-files"
	CONFIG_SHELL=sh

Notice the -Zexe flag. It is here to ease your work: if you use it, you will not need to edit the Makefile. OTOH, it is a temporary solution. See below for more on program name extensions.

The flags can be overriden. Either edit the generated configure file or set environment variables

[From within CMD.EXE]
	set MAKE=x11make.exe
	set CFLAGS=-O2
	set CFLAGS=-O2
	set LDFLAGS=-Zexe -Zcrtdll -Zsysv-signals
[From within SH.EXE]
	export MAKE=x11make.exe
	export CFLAGS=-O2
	export CFLAGS=-O2
	export LDFLAGS="-Zexe -Zcrtdll -Zsysv-signals"

or let the configure program run and, at the end, edit config.status changing the variables to suit your needs. (See below)

The default settings are good for X11 programs and won't harm when porting any other kind of application. If you opt to use them, please follow these two rules (extracted from the XFreeOS/2 porting guide):

You'll have problems with code declaring errno as a global variable:
```
	extern int errno;
```
Autoconf-ready code shouldn't cause this problem but if it does, enclose the sentence with a #ifdef __EMX__, and make sure the program or library includes #include <errno.h>. This is a temporary solution: you should tell the author of the application about this unportable feature (we are not only speaking about OS/2) and recommend him/her to check the existence of <errno.h> with an appropiate rule.
Because of the -Zbin-files you'll need to introduce explicit file mode flags (O_BINARY, O_TEXT, "t", "b") in the code. If you do so, use #ifdef __EMX__ to selectively introduce the patches.

The config.status file

This script contains all of the configuration parameters and is responsible for converting the *.in files into usable ones. Some tips about this script:

Invoking it directly
```
[From within CMD.EXE]
	sh config.status
[From within SH.EXE]
	config.status
```
will reprocess all af the *.in files. This is useful when you want to discard changes introduced in the makefiles or in config.h.

Instead of running configure a second time, you can edit it to change the value of any configuration parameter. For example, you could change

	s%@CFLAGS@%-O2 -Zmt%g
	s%@CXXFLAGS@%-O2 -Zmt%g
	s%@LDFLAGS@%-Zexe -Zmt -Zcrtdll -Zsysv-signals -Zbinfiles%g

	s%@CFLAGS@%-O2%g
	s%@CXXFLAGS@%-O2%g
	s%@LDFLAGS@%-Zexe -Zcrtdll -Zsysv-signals%g

thus removing the already commented flags (See above).

You should invoke config.status whenever
- you change any *.in file,
- config.status changes,
- config.status is invoked from within a makefile and causes an error: you should break the make process, invoke config.status and invoke make.exe again.

Non portable rules

There are that programs need to guess system dependent features that Autoconf currently doesn't know about. This is usually achieved with rules that are stored in aclocal.m4. Some of these rules are just a set of standard checks put together, but some other are non-portable ones (in the sense that they may not work under OS/2).

The following sections explain how rules are to be modified in order to make them OS/2 compatible. These changes are simple ones and should be notified to the maintainers together with an explanation of where to get this port of Autoconf and its compatible nature.

File names

This release introduces four macros that format file names. They are:

Name	Definition	Output (OS/2)	Output (Unix)	Target
AC_EXE_NAME(file)	file${EXE_EXT}	file.exe	file	Binary executable file
AC_SCR_NAME(file)	file${SCR_EXT}	file.cmd	file	Script file
AC_LIB_NAME(file)	${LIB_PRE}file${LIB_EXT}	file.a	libfile.a	Library file (Static)
AC_OBJ_NAME(file)	file${OBJ_EXT}	file.o	file.o	Object file

You should replace ocurrences of unix formatted names with the appropiate rule. For example

	if test -s $ac_dir/ld; then
	  ac_prog_LD=$ac_dir/ld
	else
	  ...
	fi

should become

	if test -s $ac_dir/AC_EXE_NAME(ld); then
	  ac_prog_LD=$ac_dir/AC_EXE_NAME(ld)
	else if test -s $ac_dir/AC_SCR_NAME(ld); then
	  ac_prog_LD=$ac_dir/AC_SCR_NAME(ld)
	else
	  ...
	fi
	fi

The fixed code now understands the right names in OS/2 and adds the possibility of the program (ld) being wrapped with a batch script. Notice the double fi.

Path separators

In this release of autoconf two new important macros are introduced that ease handling pathnames. The first one is AC_JOIN_PATHS. It performs two tasks:

If any of the parameters is $PATH, it is replaced with $FPATH so that the fixed version is used.
All of the parameters are concatenated using the appropiate path separator, which is stored in the PATH_IFS environment variable and is ";" under OS/2 and ":" elsewhere.

An example of code that has to be fixed using this rule is this one:

	AC_PATH_PROG(INETD, inetd, /usr/libexec/inetd,
	  $PATH:/usr/libexec:/usr/sbin:/usr/etc:etc)

The fixed version looks like this:

	AC_PATH_PROG(INETD, inetd, /usr/libexec/inetd,
	  AC_JOIN_PATHS($PATH,/usr/libexec,/usr/sbin,/usr/etc,etc)

Path search

The second important macro designed to handle pathnames is AC_LOOP_OVER_PATH. Its definition is as follows:

AC_DEFUN(AC_LOOP_OVER_PATH,
[  IFS="${IFS= 	}"; ac_save_ifs="$IFS"; IFS="${IFS}$PATH_IFS"
  for ac_dir in ifelse($#, 2, [AC_FORMAT_PATH([$2$ac_dummy])], $FPATH); do
$1
  done
  IFS="$ac_save_ifs"
])

It takes two parameters:

An optional path name. If it is not supplied, then FPATH, the fixed copy of PATH, is used. If supplied it must be properly formatted, usually with AC_JOIN_PATHS.
An action that will be performed on every directory of the supplied path. The action is nothing but a piece of sh-script. The loop is exited with a break statement and the value of the current directory is stored in the environment variable ac_dir.

An example of a rule that should be written using this macro is the following piece of code extracted form Libtool's aclocal.m4:

	[case "$LD" in
	  /*)
	  ac_cv_path_LD="$LD" # Let the user override the test with a path.
	  ;;
	  *)
	  IFS="${IFS= 	}"; ac_save_ifs="$IFS"; IFS="${IFS}:"
	  for ac_dir in $PATH; do
	    test -z "$ac_dir" && ac_dir=.
	    if test -f "$ac_dir/ld"; then
		...
	    fi
	  done
	  IFS="$ac_save_ifs"
	  ;;
	esac])

The fixed version is

	[case "$LD" in
	  /*|[a-zA-Z]:*)
	  ac_cv_path_LD="$LD" # Let the user override the test with a path.
	  ;;
	  *)
	AC_LOOP_OVER_PATH(
	[    test -z "$ac_dir" && ac_dir=.
	    if test -f "$ac_dir/AC_EXE_NAME(ld)"; then
		...
	    fi])
	esac])

Bug reports

If you miss a feature in autoconf, or find something doesn't work, please e-mail me.

When reporting bugs, follow these steps:

Make sure you have the required utilities configured and properly installed in your system.
If autoconf crashes, use
```
[From CMD.EXE and SH.EXE:]
	sh -x d:/usr/local/bin/autoconf 2>&1 1>error0.log
```
to invoke it and e-mail me the error0.log file. Notice the use of Autoconf's full path name and the lack of the -c option.
If it's configure the one that fails, use
```
	autoconf --debug
```
to rebuild the configure script that doesn't seem to work.
Run the rebuilt file with something like
```
	configure 2>&1 error.log
```
and e-mail me the error.log, config.log, config.status and config.cache files. You should also send me any *.in and *.m4 files. You can pack them with any well-known archiver (ZIP, tar+gzip, LZH, ZOO).
Be patient :)

Greetings and notes

I must thank Alexander Mai for his many comments on the project, and T.E.Dickey for pointing out some bugs.

Remember:

This is work in progress, don't expect miracles!!!
This is GPL software
All usual disclaimers apply
Read the file ChangesLog.os2 for important changes, features and maybe bugs.

Getting it

So... here are GNU Autoconf 2.12 for EMX, sources (400k long) and GNU Autoconf 2.12 for EMX, precompiled (236k long)

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Maintainer: Juan Jose Garcia Ripoll