add evfb (evdev + fbdev) backend

Outside of a terminal emulator or web browser, this typing experience
can be useful outside the DE, such as in the TTY or when entering a
password for full-disk encryption. Add a target that uses the bare
hardware to allow the keyboard to be deployed in more flexible
environments.

Cargo.toml

@@ -6,6 +6,7 @@ license = "GPL-3.0-only"
 
 [dependencies]
 ashpd = { version = "0.11", features = ["wayland"] }
+evdev = "0.13"
 fontconfig = "0.9"
 # Disable freetype-sys, as it vendors libfreetype2 while fontconfig dynamically
 # links to it. Large dependencies should not be duplicated.
@@ -13,10 +14,12 @@ freetype = { version = "0.7", default-features = false }
 futures-util = "0.3"
 imgref = "1"
 libc = "0.2"
+linux-raw-sys = { version = "0.9", features = ["ioctl"] }
 memmap2 = "0.9"
 polling = "3"
 reis = "0.4"
 rgb = "0.8"
+signal-hook = "0.3"
 tokio = { version = "1", features = ["macros", "rt"] }
 wayland-backend = "0.3"
 wayland-client = "0.31"
@@ -30,6 +33,10 @@ zbus = { version = "5", default-features = false, features = ["tokio"] }
 [build-dependencies]
 bindgen = "0.71"
 
+[[bin]]
+name = "ufkbd-evfb"
+path = "src/ufkbd_evfb.rs"
+
 [[bin]]
 name = "ufkbd-gnome"
 path = "src/ufkbd_gnome.rs"