	     Building and Installing Emacs from the Repository

The Emacs repository is hosted on Savannah.  The following Git command
will clone the repository to the 'emacs' subdirectory of the current
directory on your local machine:

    git clone https://git.savannah.gnu.org/git/emacs.git

To build the repository code, simply run 'make' in the 'emacs'
directory.  This should work if your files are freshly checked out
from the repository, and if you have the proper tools installed; the
default configuration options will be used.  Other configuration
options can be specified by setting a 'configure' variable, for
example:

  $ make configure="--prefix=/opt/emacs CFLAGS='-O0 -g3'"

(We recommend the above CFLAGS if you want to build Emacs that will
be easy to debug.  In addition, including --enable-checking=all in
the value of 'configure' above will turn on many run-time checks
that will identify problematic code sooner rather than later.)

If the above doesn't work, or if you have special build requirements,
the following information may be helpful.

Building Emacs from the source-code repository requires some tools
that are not needed when building from a release.  You will need:

autoconf  - at least the version specified near the start of
  configure.ac (in the AC_PREREQ command).
git - at least Git 1.7.1.  If your repository was created by an older
  Git version, you may need to reclone it.
makeinfo  - required to build the manuals (whose Info files are not
  in the repository).  Installing GNU Texinfo 4.13 or later should
  work.

To use the autotools, run the following shell command to generate the
'configure' script and some related files, and to set up your git
configuration:

  $ ./autogen.sh

You can then configure your build as follows:

  $ ./configure

The 'configure' script has many options; run './configure --help' to
see them.  For example, if you want later builds to go faster, albeit
sometimes doing the wrong thing if you update the build procedure, you
can invoke './configure -C'.  After configuring, build Emacs as follows:

  $ make

You can also type 'make check' to test and 'make install' to install
Emacs.

Occasionally the file 'lisp/loaddefs.el' (and similar automatically
generated files, such as 'esh-groups.el', and '*-loaddefs.el' in some
subdirectories of 'lisp/', e.g., 'mh-e/' and 'calendar/') will need to be
updated to reflect new autoloaded functions.  If you see errors (rather
than warnings) about undefined lisp functions during compilation, that
may be the reason.  Finally, sometimes there can be build failures
related to '*loaddefs.el' (e.g., "required feature ‘esh-groups’ was not
provided").  In that case, follow the instructions below.

To update loaddefs.el (and similar files), do:

  $ cd lisp
  $ make autoloads

If either of the above partial procedures fails, try 'make bootstrap'.
If CPU time is not an issue, 'make bootstrap' is a more thorough way
to rebuild, avoiding spurious problems.  'make bootstrap' rebuilds
Emacs with the same configuration options as the previous build; it
can also be used to rebuild Emacs with other configuration options by
setting a 'configure' variable, for example:

  $ make bootstrap configure="CFLAGS='-O0 -g3'"

To rebuild Emacs with the default configuration options, you can use:

  $ make bootstrap configure=default

Occasionally, there are changes that 'make bootstrap' won't be able to
handle.  The most thorough cleaning can be achieved by 'git clean -fdx'
which will leave you with only files from the git repository.  Here
are some faster methods for a couple of particular error cases:

    /usr/bin/m4:aclocal.m4:9: cannot open `m4/stdbit_h.m4': No such file or directory

This can be fixed with 'rm aclocal.m4'.

    make: *** No rule to make target 'lib/Makefile.am', needed by 'lib/Makefile.in'

This can be fixed with 'rm lib/Makefile Makefile'.

Because the repository version of Emacs is a work in progress, it will
sometimes fail to build.  Please wait a day or so (and check the
archives of the emacs-buildstatus, emacs-devel, and bug-gnu-emacs
mailing lists) before reporting such problems.  In most cases, the
problem is known about and is just waiting for someone to fix it.
This is especially true for Lisp compilation errors, which are almost
never platform-specific.

If you need to debug Emacs, the instructions in 'etc/DEBUG' will help.
You can display that file in Emacs with 'C-h C-d', or just read it with
any program that can display text files, such as Less.


Copyright (C) 2002-2025 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
