stage1: fix wasi_snapshot_preview1_fd_seek on cache files

Author: mlugg

build.zig

@@ -12,7 +12,7 @@ const DevEnv = @import("src/dev.zig").Env;
 const ValueInterpretMode = enum { direct, by_name };
 
 const zig_version: std.SemanticVersion = .{ .major = 0, .minor = 15, .patch = 0 };
-const stack_size = 46 * 1024 * 1024;
+const stack_size = 50 * 1024 * 1024;
 
 pub fn build(b: *std.Build) !void {
     const only_c = b.option(bool, "only-c", "Translate the Zig compiler to C code, with only the C backend enabled") orelse false;

stage1/wasi.c

@@ -1003,6 +1003,8 @@ uint32_t wasi_snapshot_preview1_fd_seek(uint32_t fd, uint64_t in_offset, uint32_
         default: panic("unimplemented");
     }
 
+    if (fds[fd].stream == NULL) return wasi_errno_success;
+
     int seek_whence;
     switch (whence) {
         case wasi_whence_set: