restrict linkage to platforms using ELF binaries

on windows and apple (which don't use ELF) we can't apply weak linkage

Author: Lokathor

src/arm.rs

@@ -22,7 +22,7 @@ intrinsics! {
     // custom calling convention which can't be implemented using a normal Rust function.
     #[naked]
     #[cfg(not(target_env = "msvc"))]
-    #[linkage = "weak"]
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
     pub unsafe extern "C" fn __aeabi_uidivmod() {
         core::arch::asm!(
             "push {{lr}}",
@@ -37,7 +37,7 @@ intrinsics! {
     }
 
     #[naked]
-    #[linkage = "weak"]
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
     pub unsafe extern "C" fn __aeabi_uldivmod() {
         core::arch::asm!(
             "push {{r4, lr}}",
@@ -54,7 +54,7 @@ intrinsics! {
     }
 
     #[naked]
-    #[linkage = "weak"]
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
     pub unsafe extern "C" fn __aeabi_idivmod() {
         core::arch::asm!(
             "push {{r0, r1, r4, lr}}",
@@ -68,7 +68,7 @@ intrinsics! {
     }
 
     #[naked]
-    #[linkage = "weak"]
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
     pub unsafe extern "C" fn __aeabi_ldivmod() {
         core::arch::asm!(
             "push {{r4, lr}}",