zephyr-sys: Export stack alignment constants

Bindgen only exports defined values that are clearly numeric constants,
which is thrown off when the defined value has a cast.  Work around this
by defining wrapper constants that bindgen is able to expose.

We use the `ZR_` prefix (Zephyr Rust) to avoid conflicts with any other
symbols.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

zephyr-sys/build.rs

@@ -71,6 +71,7 @@ fn main() -> Result<()> {
         .allowlist_function("k_.*")
         .allowlist_function("gpio_.*")
         .allowlist_function("sys_.*")
+        .allowlist_item("ZR_.*")
         // Deprecated
         .blocklist_function("sys_clock_timeout_end_calc")
         .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))

zephyr-sys/wrapper.h

@@ -31,4 +31,15 @@ extern int errno;
 #endif
 
 #include <zephyr/kernel.h>
+#include <zephyr/kernel/thread_stack.h>
 #include <zephyr/drivers/gpio.h>
+
+/*
+ * bindgen will output #defined constant that resolve to simple numbers.  There are some symbols
+ * that we want exported that, at least in some situations, are more complex, usually with a type
+ * case.
+ *
+ * We'll use the prefix "ZR_" to avoid conflicts with other symbols.
+ */
+const uintptr_t ZR_STACK_ALIGN = Z_KERNEL_STACK_OBJ_ALIGN;
+const uintptr_t ZR_STACK_RESERVED = K_KERNEL_STACK_RESERVED;