Flip arch default.

The Arm version requires a dependency that is only available when the target is thumbv8m.main-none-eabihf. The RISC-V version compiles on any target.

With this change, you can compile the PAC for, say, aarch64-apple-darwin, without errors. It won't work, obviously, but it'll compile.

.cargo/config.toml

@@ -1,3 +1,3 @@
 [build]
 # Set a default target so the docs build
-target = "thumbv8m.main-none-eabihf"
+target = "riscv32imac-unknown-none-elf"

src/lib.rs

@@ -13,14 +13,14 @@
 
 // Use the Cortex-M version by default
 
-#[cfg(not(target_arch = "riscv32"))]
+#[cfg(target_arch = "arm")]
 #[doc(hidden)]
 #[path = "inner/mod_cortex_m.rs"]
 mod inner;
 
 // On riscv32*-*-* use the RISC-V version
 
-#[cfg(target_arch = "riscv32")]
+#[cfg(not(target_arch = "arm"))]
 #[doc(hidden)]
 #[path = "inner/mod_risc_v.rs"]
 mod inner;