+ Works on several machines.
+
+Berkeley 4.3 (bsd4.3)
+
+ Works, on Vaxes at least.
+
+Esix
+
+ The following was written for Emacs 18.59 and has been
+ slightly adapted for Emacs 19. It may need more change to be correct.
+
+ Use s/usg5-4.h for Esix System V 4.0.[34] systems if you also have
+ XFree86. If you insist on using the Esix X Window libraries, good
+ luck. s/esix5r4.h provides a starting point, but doesn't seem to
+ work consistently. The basic problems involve the need to load
+ -lX11 *last* in the link command, and even then some things break.
+ You get best results by installing XFree86 and forgetting about the
+ Esix stuff unless you want to run IXI xdt3, which really only needs
+ the Esix X11 shared libraries.
+
+ To compile with XFree86, make sure that your LD_LIBRARY_PATH
+ contains /usr/X386/lib. Be careful if you also have the Esix X
+ Window libraries that /usr/X386/lib appears *first* in the
+ LD_LIBRARY_PATH. Then define C_SWITCH_X_SYSTEM -I/usr/X386/include.
+
+Linux (actually GNU/Linux)
+
+ Most of the complete systems which use the Linux kernel are close
+ enough to the GNU system to be considered variant GNU systems. We
+ call them "Linux-based GNU systems," or GNU/Linux for short.
+
+ It is not coincidence that many of the other components used with
+ Linux--including GNU Emacs--were developed specifically for the GNU
+ project. The GNU project was launched in 1984 to develop a free
+ complete Unix-like operating system. To reach this goal, we had to
+ develop whatever system components were not available as freely
+ redistributable software from some other source.
+
+ The GNU project wants users of GNU/Linux systems to be aware of how
+ these systems relate to the GNU project, because that will help
+ spread the GNU idea that software should be free--and thus encourage
+ people to write more free software. See the file LINUX-GNU in this
+ directory for more explanation.
+
+Microport
+
+ See under "Intel 386".
+
+MSDOS
+
+ For installation on MSDOS, see the file INSTALL (search for `MSDOG',
+ near the end of the file). See the "MS-DOS" chapter of the manual
+ for information about using Emacs on MSDOS.
+
+SCO Unix
+ If you have TCP but not X, you need to edit src/s/sco4.h
+ to define HAVE_SOCKETS.
+
+ If you are using MMDF instead of sendmail, you need to remove
+ /usr/lib/sendmail or modify lisp/paths.el before compiling.
+ lisp/paths.el (which is loaded during the build) will attempt to use
+ sendmail if it exists.
+
+ If you are using SMAIL, you need to define the macro
+ SMAIL in config.h.
+
+System V rel 0 (usg5.0)
+
+ Works, on Vaxes and 3bxxx's.
+ There are some problems in 18.37 due to shortnames/cccp problems:
+ use the emacs 17 cpp if you have it.
+
+System V rel 2 (usg5.2)
+
+ Works on various machines.
+ On some (maybe all) machines the library -lPW exists and contains
+ a version of `alloca'. On these machines, to use it, put
+ #define HAVE_ALLOCA
+ #define LIB_STANDARD -lPW -lc
+ in the `src/m/MACHINENAME.h' file for the machine.
+
+ If you find that the character Meta-DEL makes Emacs crash,
+ find where function init_sys_modes in sysdep.c sets sg.c_cc[VQUIT]
+ and make it store 7 there. I have as yet no evidence of whether
+ this problem, known in HP/UX, exists in other system V versions.
+
+System V rel 2.2 (usg5.2.2)
+
+ In 5.2.2 AT&T undid, incompatibly, their previous incompatible
+ change to the way the nlist library is called. A different s- file
+ is used to enable the other interface.
+
+ They call themselves the right choice--can't they choose?
+
+ Emacs version 18 unexec is currently not working properly
+ on 5.2.2. Nobody knows why yet. A workaround is to define
+ NO_REMAP. It is not yet known whether this applies to all
+ machines running 5.2.2.
+
+System V rel 3 (usg5.3)
+
+ Some versions of this system support ptys and BSD-style sockets.
+ On such systems, you should define HAVE_PTYS and HAVE_SOCKETS in config.h.
+
+ If you want to link Emacs with shared libraries, define
+ USG_SHARED_LIBRARIES.
+
+ You may have to add ANSI idempotence #-lines to your sys/types.h
+ file to get Emacs to compile correctly. This may be necessary on
+ other pre-ANSI systems as well.
+
+ On an AT&T 6386WGS using System V Release 3.2 and X11R3, the X support
+ cannot be made to work. Whether or not the GNU relocating malloc is
+ used, the symptom is that the first call Emacs makes to sbrk(0) returns
+ (char *)-1. Sorry, you're stuck with character-only mode. Try
+ installing Xfree86 to fix this.
+
+System V rel 4.0.3 and 4.0.4 (usg5.4)
+
+ Supported, including shared libraries for ELF, but ptys do not work
+ because TIOCGPGRP fails to work on ptys (but Dell 2.2 seems to have
+ fixed this). This failure is probably due to a misunderstanding of
+ the consequences of the POSIX spec: many system designers mistakenly
+ think that POSIX requires this feature to fail. This is untrue;
+ ptys are an extension, and POSIX says that extensions *when used*
+ may change the action of standard facilities in any fashion.
+
+ If you get compilation errors about wrong number of
+ arguments to getpgrp, define GETPGRP_NO_ARG.
+
+ The standard C preprocessor may generate xmakefile incorrectly. However,
+ /lib/cpp will work, so use `make CPP=/lib/cpp'. Standard cpp
+ seems to work OK under Dell 2.2.
+
+ Some versions 3 and earlier of V.4, on the Intel 386 and 860, had
+ problems in the X11 libraries. These prevent Emacs from working
+ with X. You can use Emacs with X provided your copy of X is based
+ on X11 release 4 or newer, or is Dell's 2.2 (which is a 4.0.3).
+ Unfortunately, the only way you can tell whether your X11 library is
+ new enough is to try compiling Emacs to use X. If emacs runs, your
+ X11 library is new enough.
+
+ In this context, GSV4 and GSV4i are alternate names for X11R4.
+ OL2.* is X11R3 based. OL3 is in between X11R3 and X11R4, and may or
+ may not work, depending on who made the Unix system. If the library
+ libXol is part of the X distribution, then you have X11R3 and Emacs
+ won't work with X.
+
+ Most versions of V.4 support sockets. If `/usr/lib/libsocket.so'
+ exists, your system supports them. If yours does not, you must add
+ #undef HAVE_SOCKETS in config.h, after the inclusion of s-usg5-4.h.
+ (Any system that supports Internet should implement sockets.)
+
+Ultrix (bsd4.3)
+
+ Recent versions of Ultrix appear to support the features of Berkeley 4.3.
+ Ultrix was at the BSD 4.2 level for a long time after BSD 4.3 came out.
+
+ Ultrix 3.0 has incompatibilities in its X library if you have the
+ Ultrix version of X (UWS version 2.0). To solve them, you need to
+ prevent XvmsAlloc.o in Xlib from being used. Israel Pinkas says:
+
+ I added the following lines to config.h after the X defines:
+
+ #if defined(ultrix) && defined(X11)
+ #define OBJECTS_SYSTEM calloc.o
+ #endif
+
+ Then I ran the following:
+
+ ar x /usr/lib/libc.a calloc.o
+
+ The problem is said to be gone in UWS version 2.1.
+
+Uniplus 5.2 (unipl5.2)
+
+ Works, on Dual machines at least.
+
+VMS (vmsM.N)
+
+ Richard Levitte <levitte@e.kth.se> distributes a set of patches to
+ Emacs 18.59 to make it work nicely under VMS. Emacs 19 probably
+ won't work very well, or even compile. Levitte is working on a
+ port, so these problems should be fixed in the near future.
+
+ Note that Emacs for VMS is usually distributed in a special VMS
+ distribution. See the file ../vms/VMSINSTALL for info on moving
+ Unix distributions to VMS, and other VMS-related topics.
+
+Windows NT/95/98/ME/2000
+
+ For installation on all versions of the MS-Windows platform, see the
+ file nt/INSTALL.
+
+Xenix (xenix)
+
+ Should work in 18.50, but you will need to edit the files
+ `lib-src/Makefile' and `src/ymakefile'
+ (see the comments that mention "Xenix" for what to change.)
+ Compiling Emacs with -O is said not to work.
+
+ If you want Emacs to work with Smail (installed as /usr/bin/smail)
+ then add the line #define SMAIL to config.h.
+
+ The file etc/XENIX suggests some useful things to do to Xenix
+ to make the Emacs meta key work.