Fetch: enhance Mach-O executable detection for modern Macs

Author: mlafeldt

src/Package/Fetch.zig

@@ -1850,7 +1850,11 @@ const FileHeader = struct {
         return magic_number == std.macho.MH_MAGIC or
             magic_number == std.macho.MH_MAGIC_64 or
             magic_number == std.macho.FAT_MAGIC or
-            magic_number == std.macho.FAT_MAGIC_64;
+            magic_number == std.macho.FAT_MAGIC_64 or
+            magic_number == std.macho.MH_CIGAM or
+            magic_number == std.macho.MH_CIGAM_64 or
+            magic_number == std.macho.FAT_CIGAM or
+            magic_number == std.macho.FAT_CIGAM_64;
     }
 
     pub fn isExecutable(self: *FileHeader) bool {
@@ -1875,6 +1879,11 @@ test FileHeader {
     h.bytes_read = 0;
     h.update(&macho64_magic_bytes);
     try std.testing.expect(h.isExecutable());
+
+    const macho64_cigam_bytes = @byteSwap(macho64_magic_bytes);
+    h.bytes_read = 0;
+    h.update(&macho64_cigam_bytes);
+    try std.testing.expect(h.isExecutable());
 }
 
 // Result of the `unpackResource` operation. Enables collecting errors from