Add basic install script and icon

The icon comes from "Smoothicons 7" by Corey Marion which I found
as a royalty free icon searching the internet.  I would love to
have a purpose built icon, but this is sufficient for now.

The install script sets up a macOS application bundle that references
the generated wezterm binary and the icon.  The same technique could
be used to generate a .desktop file for linux.

I've changed the default-prog on macos to be `login -pf $USER` as
that is a better default experience on macOS.

.gitignore

@@ -1,3 +1,4 @@
+.DS_Store
 /Cargo.lock
 /target/
 **/*.rs.bk

assets/macos/WezTerm.app/Contents/Info.plist

@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>en</string>
+  <key>CFBundleExecutable</key>
+  <string>wezterm</string>
+  <key>CFBundleIdentifier</key>
+  <string>com.github.wez.wezterm</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>WezTerm</string>
+  <key>CFBundlePackageType</key>
+  <string>APPL</string>
+  <key>CFBundleShortVersionString</key>
+  <string>0.1.0</string>
+  <key>CFBundleSupportedPlatforms</key>
+  <array>
+    <string>MacOSX</string>
+  </array>
+  <key>CFBundleVersion</key>
+  <string>1</string>
+  <key>CFBundleIconFile</key>
+  <string>terminal.icns</string>
+  <key>NSHighResolutionCapable</key>
+  <true/>
+  <key>NSMainNibFile</key>
+  <string></string>
+  <key>NSSupportsAutomaticGraphicsSwitching</key>
+  <true/>
+  <key>CFBundleDisplayName</key>
+  <string>WezTerm</string>
+  <key>NSRequiresAquaSystemAppearance</key>
+  <string>NO</string>
+    <key>NSAppleEventsUsageDescription</key>
+    <string>An application launched via WezTerm would like to access AppleScript.</string>
+    <key>NSCalendarsUsageDescription</key>
+    <string>An application launched via WezTerm would like to access calendar data.</string>
+    <key>NSCameraUsageDescription</key>
+    <string>An application launched via WezTerm would like to access the camera.</string>
+    <key>NSContactsUsageDescription</key>
+    <string>An application launched via WezTerm wants to access your contacts.</string>
+    <key>NSLocationAlwaysUsageDescription</key>
+    <string>An application launched via WezTerm would like to access your location information, even in the background.</string>
+    <key>NSLocationUsageDescription</key>
+    <string>An application launched via WezTerm would like to access your location information.</string>
+    <key>NSLocationWhenInUseUsageDescription</key>
+    <string>An application launched via WezTerm would like to access your location information while active.</string>
+    <key>NSMicrophoneUsageDescription</key>
+    <string>An application launched via WezTerm would like to access your microphone.</string>
+    <key>NSRemindersUsageDescription</key>
+    <string>An application launched via WezTerm would like to access your reminders.</string>
+</dict>
+</plist>

install.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+case $OSTYPE in
+  darwin*)
+    APP=$HOME/Applications/WezTerm.app
+    cargo build --release
+    rm -rf $APP
+    cp -r assets/macos/WezTerm.app $APP
+    cp target/release/wezterm $APP
+    echo "Installed to $APP"
+    ;;
+  *)
+    echo "Don't know how to install the app on this system"
+    exit 1
+    ;;
+esac

src/config.rs

@@ -381,10 +381,37 @@ impl Config {
         cfg
     }
 
+    /// On macOS, we get launched from: eg: spotlight or alfred
+    /// or the finder with whatever SHELL was set to at login time
+    /// (which have been subsequently changed via `chsh`) and with
+    /// a cwd=/.
+    /// That feels a bit broken, so we follow the lead of
+    /// Terminal.app and use `login -pf $USER` as the default
+    /// program to run.
+    /// This function computes and returns that command.
+    /// We don't do this on Linux because the linux `login`
+    /// program refuses to run except when started by root.
+    #[cfg(target_os = "macos")]
+    fn macos_login() -> Result<Vec<String>, Error> {
+        let ent = unsafe { libc::getpwuid(libc::getuid()) };
+        if ent.is_null() {
+            bail!("unable to resolve my own uid");
+        } else {
+            let name = unsafe { std::ffi::CStr::from_ptr((*ent).pw_name) };
+            let name = name.to_str().map(str::to_owned)?;
+            Ok(vec!["login".to_owned(), "-pf".to_owned(), name])
+        }
+    }
+
     pub fn default_prog(&self) -> Result<Vec<String>, Error> {
         if let Some(prog) = self.default_prog.as_ref() {
             Ok(prog.clone())
         } else {
+            if cfg!(target_os = "macos") {
+                if let Ok(login) = Self::macos_login() {
+                    return Ok(login);
+                }
+            }
             Ok(vec![get_shell()?])
         }
     }