Does emacs have an option or some internal command that displays build time settings and whatever features it supports?
A good example is the
nginx -V command which lists the
./configure options it was compiled with.
Take a look at the
Here's an example, which is the result of running
C-h v system-configuration-options
system-configuration-options is a variable defined in `C source code'. Its value is "--prefix=/usr/local/emacs 'CFLAGS=-O2 -march=native -pipe -falign-functions=64 -fomit-frame-pointer -ftracer -funit-at-a-time -fweb -fforce-addr -fpeel-loops -funswitch-loops -frename-registers -mfpmath=sse -ffast-math -fno-finite-math-only -fstack-check' PKG_CONFIG_PATH=/usr/share/pkgconfig" Documentation: String containing the configuration options Emacs was built with. For more information check the manuals.
Dunno about a command-line switch, but:
If you use library
emacsbug+.el, which enhances standard library
emacsbug.el, then you can use command
ebp-insert-version with a prefix arg, to insert the complete version info, including some build info, in the current buffer. This is the same version info that is included when you use command
report-emacs-bug. For example:
In GNU Emacs 25.2.1 (x86_64-w64-mingw32) of 2017-04-24 Windowing system distributor `Microsoft Corp.', version 6.1.7601 Configured using: `configure --without-dbus --without-compress-install 'CFLAGS=-O2 -static -g3''
emacsbug+.el, you can use standard command
emacs-version, to give you a subset of that info. With a prefix arg it inserts the info in the current buffer. For example:
GNU Emacs 25.2.1 (x86_64-w64-mingw32) of 2017-04-24