build(wasi): change __cxa_init_primary_exception shim return

For:

│ wasm-ld: warning: function signature mismatch: __cxa_init_primary_exception
│ >>> defined as (i32, i32, i32) -> i32 in lto.tmp
│ >>> defined as (i32, i32, i32) -> void in libwasi-itk-extras.a(exceptionShimInitPrimaryException.cxx.o)

Author: thewtex

src/exceptionShimInitPrimaryException.cxx

@@ -25,7 +25,7 @@
 extern "C" {
 
 // Only triggered with Debug wasi-threads builds
-void __cxa_init_primary_exception(void *, void *, void *)
+int __cxa_init_primary_exception(void *, void *, void *)
 {
 }