Fix feature checking in cross builds

Checking for target os in build.rs doesn't work, since build.rs
is running for host, so checking should be done in src. Thus moving
'compile_error!' check from build.rs to main.rs.

1 files changed, 3 insertions, 0 deletions

diff --git a/alacritty/src/main.rs b/alacritty/src/main.rs
index 09296f60..19ae917b 100644
--- a/alacritty/src/main.rs
+++ b/alacritty/src/main.rs
@@ -8,6 +8,9 @@
 // See https://msdn.microsoft.com/en-us/library/4cc7ya5b.aspx for more details.
 #![windows_subsystem = "windows"]
 
+#[cfg(not(any(feature = "x11", feature = "wayland", target_os = "macos", windows)))]
+compile_error!(r#"at least one of the "x11"/"wayland" features must be enabled"#);
+
 #[cfg(target_os = "macos")]
 use std::env;
 use std::error::Error;