Split out capi targets: make separate freertos, staticlib, and cdylib crates as targets

ffi/diplomat/Cargo.toml

@@ -33,7 +33,7 @@ skip_optional_dependencies = true
 # Bench feature gets tested separately and is only relevant for CI.
 # x86tiny is not relevant in normal environments,
 # smaller_static gets tested on the FFI job anyway
-denylist = ["bench", "x86tiny", "smaller_static"]
+denylist = ["bench", "x86tiny", "smaller_static", "internal_all_features_hack"]
 
 [lib]
 crate-type = ["rlib"]
@@ -47,6 +47,9 @@ provider_static = ["icu_testdata"]
 smaller_static = ["provider_static"]
 # Enables size-optimized builds on x86_64
 x86tiny = ["dlmalloc"]
+# We can't exclude x86tiny from `--all-features` and it messes up the build for other crates
+# Instead, we use this feature to detect when `--all-features` is occurring
+internal_all_features_hack = []
 
 [dependencies]
 fixed_decimal = { path = "../../utils/fixed_decimal", features = ["ryu"] }

ffi/diplomat/src/lib.rs

@@ -15,7 +15,7 @@
 )]
 #![allow(clippy::upper_case_acronyms)]
 #![cfg_attr(
-    any(feature = "x86tiny", target_os = "none"),
+    all(feature = "x86tiny", not(feature = "internal_all_features_hack")),
     feature(alloc_error_handler)
 )]
 
@@ -54,5 +54,5 @@ pub mod segmenter_line;
 #[cfg(target_arch = "wasm32")]
 mod wasm_glue;
 
-#[cfg(all(feature = "x86tiny", not(target_os = "none")))]
+#[cfg(all(feature = "x86tiny", not(feature = "internal_all_features_hack")))]
 mod x86tiny_glue;

ffi/freertos/src/lib.rs

@@ -4,6 +4,7 @@
 
 // https://github.com/unicode-org/icu4x/blob/main/docs/process/boilerplate.md#library-annotations
 #![no_std]
+
 #![cfg_attr(
     not(test),
     deny(
@@ -14,28 +15,37 @@
     )
 )]
 #![allow(clippy::upper_case_acronyms)]
-#![feature(alloc_error_handler)]
 
-extern crate alloc;
+
+#![cfg_attr(target_os = "none", feature(alloc_error_handler))]
 
 // Necessary to for symbols to be linked in
 extern crate icu_capi;
 
-use alloc::alloc::Layout;
-use core::panic::PanicInfo;
-use cortex_m::asm;
-use freertos_rust::FreeRtosAllocator;
+// CFG it off so that it doesn't break the --all-features build due to needing unstable rust
+#[cfg(target_os = "none")]
+mod stuff {
+    extern crate alloc;
 
-#[global_allocator]
-static GLOBAL: FreeRtosAllocator = FreeRtosAllocator;
 
-#[alloc_error_handler]
-fn alloc_error(_layout: Layout) -> ! {
-    asm::bkpt();
-    loop {}
-}
+    use alloc::alloc::Layout;
+    use core::panic::PanicInfo;
+    use cortex_m::asm;
+    use freertos_rust::FreeRtosAllocator;
+
+    #[global_allocator]
+    static GLOBAL: FreeRtosAllocator = FreeRtosAllocator;
+
+
+    #[alloc_error_handler]
+    fn alloc_error(_layout: Layout) -> ! {
+        asm::bkpt();
+        loop {}
+    }
 
-#[panic_handler]
-fn panic(_info: &PanicInfo) -> ! {
-    loop {}
+    #[cfg(target_os = "none")]
+    #[panic_handler]
+    fn panic(_info: &PanicInfo) -> ! {
+        loop {}
+    }
 }