fix: stage2 compatibility

src/main.zig

@@ -5,7 +5,7 @@ const testing = std.testing;
 pub fn log(
     /// The value returned by @cImport.
     /// Must include the "glib.h" or "glib/gmessages.h" header.
-    c: anytype,
+    comptime c: type,
     /// The name of the module used for the log output.
     comptime module_name: []const u8,
     /// The length of the buffer used for the formatted output.
@@ -15,7 +15,7 @@ pub fn log(
     return LogStruct(c, module_name, buf_size).log;
 }
 
-fn LogStruct(c: anytype, comptime module_name: []const u8, comptime buf_size: usize) type {
+fn LogStruct(comptime c: type, comptime module_name: []const u8, comptime buf_size: usize) type {
     return struct {
         threadlocal var fmt_buf: [buf_size]u8 = undefined;
 
@@ -66,3 +66,7 @@ fn LogStruct(c: anytype, comptime module_name: []const u8, comptime buf_size: us
         }
     };
 }
+
+test {
+    std.testing.refAllDecls(@This());
+}