Enable all terminal emulators by default

We can't enable features in build.rs, see
rust-lang/cargo#5499, and cargo doesn't
support target-specific default features, see
rust-lang/cargo#1197.

Essentially we build as we used to do before we added features for
terminal emulators.  Downsides are more dependencies than needed—you
don’t need iterm2 on Linux after all—and Windows doesn't build with
default features at all.

This reverts commit 544943a.

.appveyor.yml

@@ -16,14 +16,14 @@ install:
   # syntect)
   - call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"
 build_script:
-  - cargo build --release --verbose
+  - cargo build --no-default-features --release --verbose
 after_build:
   # The leading '.\' is important to avoid a command error with -windows being
   # interpreted as flag if APPVEYOR_REPO_TAG_NAME is empty.
   - 7z a .\%APPVEYOR_REPO_TAG_NAME%-windows.zip %APPVEYOR_BUILD_FOLDER%\target\release\mdcat.exe %APPVEYOR_BUILD_FOLDER%\README.md %APPVEYOR_BUILD_FOLDER%\CHANGELOG.md %APPVEYOR_BUILD_FOLDER%\LICENSE
 test_script:
-  - cargo test --verbose
-  - cargo run -- sample/common-mark.md
+  - cargo test --no-default-features --verbose
+  - cargo run --no-default-features -- sample/common-mark.md
 artifacts:
   - path: '*.zip'
 # Deploy tags to GitHub releases

CHANGELOG.md

@@ -11,7 +11,8 @@ This project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html
 ### Changed
 - Refactor internal terminal representation, replacing the terminal enum with a
   new `Terminal` trait and dynamic dispatch (see [GH-35][]).
-- Only include terminal backends supported on the platform (see [GH-35][]).
+- Disable specific terminal backends by default (see [GH-35][]).  You must build
+  with `--feature` to enable iTerm2 or Terminology.
 - Update minimum Rust version to 1.27.
 
 [GH-33]: https://github.com/lunaryorn/mdcat/pull/33

Cargo.toml

@@ -10,16 +10,17 @@ version = "0.8.1-pre"
 categories = ["command-line-utilities", "text-processing"]
 license = "Apache-2.0"
 authors = ["Sebastian Wiesner <sebastian@swsnr.de>"]
-build = "build.rs"
 
 [badges]
 travis-ci = { repository = "lunaryorn/mdcat" }
 maintenance = { status = "actively-developed" }
 
 [features]
-default = []
+default = ["iterm2", "terminology"]
 
+# Enable special support for iTerm2.
 iterm2 = ["mime", "base64"]
+# Enable special support for Terminology.
 terminology = ["immeta"]
 
 [dependencies]

README.md

@@ -61,6 +61,9 @@ Not supported:
 Install [Rust][rustup] and run `cargo install mdcat`.  To keep mdcat up to date
 install [cargo-update][] and run `cargo install-update mdcat`.
 
+**Note:** On Windows you likely need `--no-default-features` to make `mdcat`
+build.
+
 ### SVG support
 
 `mdcat` needs `rsvg-convert` to show SVG images in [iTerm2][]; otherwise `mdcat`