[libc][hdrgen] Fix hdrgen when using macros as guards in stdlib.yaml. (#152732)

Author: bassiounix

libc/utils/hdrgen/hdrgen/header.py

@@ -204,7 +204,7 @@ def relpath(file):
 
         current_guard = None
         for function in self.functions:
-            if function.guard == None:
+            if function.guard == None and current_guard == None:
                 content.append(str(function) + " __NOEXCEPT;")
                 content.append("")
             else:
@@ -221,7 +221,8 @@ def relpath(file):
                     content.append(f"#endif // {current_guard}")
                     content.append("")
                     current_guard = function.guard
-                    content.append(f"#ifdef {current_guard}")
+                    if current_guard is not None:
+                        content.append(f"#ifdef {current_guard}")
                     content.append(str(function) + " __NOEXCEPT;")
                     content.append("")
         if current_guard != None: