Don't let the crate be built without avx2, avx, etc. or it'll be very slow.

.cargo/config

@@ -0,0 +1,2 @@
+[build]
+rustflags = ["-C", "target-feature=+avx2,+avx,+sse,+fma"]

src/main.rs

@@ -1,3 +1,12 @@
+#[cfg(not(target_feature = "avx2"))]
+compile_error!("This library assumes availability of AVX and must be compiled with -C target-feature=+sse2,+avx,+fma,+avx2");
+#[cfg(not(target_feature = "sse2"))]
+compile_error!("This library assumes availability of AVX and must be compiled with -C target-feature=+sse2,+avx,+fma,+avx2");
+#[cfg(not(target_feature = "fma"))]
+compile_error!("This library assumes availability of AVX and must be compiled with -C target-feature=+sse2,+avx,+fma,+avx2");
+#[cfg(not(target_feature = "avx"))]
+compile_error!("This library assumes availability of AVX and must be compiled with -C target-feature=+sse2,+avx,+fma,+avx2");
+
 pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     rllama::rllama_main::main()
 }