config-internal.h: automatically set ECL_C_COMPATIBLE_VARIADIC_DISPATCH for apple/arm64

INSTALL

@@ -98,7 +98,7 @@ Hint provided by Pascal J. Bourguignon.
    #+END_SRC
 3. Build and install the target library
    #+BEGIN_SRC shell-script
-     export CFLAGS="$CFLAGS -DECL_C_COMPATIBLE_VARIADIC_DISPATCH -DGC_DISABLE_INCREMENTAL -DECL_RWLOCK"
+     export CFLAGS="$CFLAGS -DGC_DISABLE_INCREMENTAL -DECL_RWLOCK"
      export CXXFLAGS="$CFLAGS"
      ./configure --host=aarch64-apple-darwin \
                  --prefix=`pwd`/ecl-iOS \

src/h/config-internal.h.in

@@ -248,3 +248,12 @@
 #else
 #define ECL_DEFAULT_C_STACK_SIZE @ECL_DEFAULT_C_STACK_SIZE@
 #endif
+
+/* Do the fixed and optional arguments of a variadic function use a
+ * different calling convention?
+ * Hardcoded since there's no easy way to determine this from a
+ * configure check and currently ARM64 apple is the only platform
+ * known to do this. */
+#if defined(__APPLE__) && (defined(__arm64__) || defined(__aarch64__))
+#define ECL_C_COMPATIBLE_VARIADIC_DISPATCH
+#endif

src/h/object.h

@@ -769,7 +769,7 @@ struct ecl_cfun {               /*  compiled function header  */
         cl_object block;        /*  descriptor of C code block for GC  */
         cl_objectfn entry;      /*  entry address  */
 #ifdef ECL_C_COMPATIBLE_VARIADIC_DISPATCH
-        /* Some architectures (i.e. ARM64 on iOS) use a different
+        /* Some architectures (i.e. ARM64 on iOS/Mac OS X) use a different
          * calling convention for the fixed and variadic arguments of
          * a variadic function. The only portable way to allow for
          * function redefinitions during runtime in these