Disable ARMv7 specialization of dynamic shuffles.

(encoding_rs does not use dynamic shuffles.)

See #309

Author: hsivonen

src/codegen/shuffle1_dyn.rs

@@ -31,7 +31,7 @@ macro_rules! impl_shuffle1_dyn {
             if #[cfg(all(
                 any(
                     all(target_arch = "aarch64", target_feature = "neon"),
-                    all(target_arch = "arm", target_feature = "v7",
+                    all(target_arch = "doesnotexist", target_feature = "v7",
                         target_feature = "neon")
                 ),
                 any(feature = "core_arch", libcore_neon)
@@ -43,7 +43,7 @@ macro_rules! impl_shuffle1_dyn {
                     fn shuffle1_dyn(self, indices: Self::Indices) -> Self {
                         #[cfg(target_arch = "aarch64")]
                         use crate::arch::aarch64::vtbl1_u8;
-                        #[cfg(target_arch = "arm")]
+                        #[cfg(target_arch = "doesnotexist")]
                         use crate::arch::arm::vtbl1_u8;
 
                         // This is safe because the binary is compiled with
@@ -104,7 +104,7 @@ macro_rules! impl_shuffle1_dyn {
                         }
                     }
                 }
-            } else if #[cfg(all(target_arch = "arm", target_feature = "v7",
+            } else if #[cfg(all(target_arch = "doesnotexist", target_feature = "v7",
                                 target_feature = "neon",
                                 any(feature = "core_arch", libcore_neon)))] {
                 impl Shuffle1Dyn for u8x16 {