Fix: Handle #pragma GCC target() in C++ bundler

When GCC preprocesses with -dD flag and encounters #pragma GCC target(),
it emits extra macro definitions for compiler features (__AVX2__, __SSE4_1__, etc).
This causes a line count mismatch in the bundler's assertion that line counts
must be equal between raw source and uncommented code.

Solution: Temporarily comment out #pragma GCC target() before preprocessing,
then uncomment in the output. Uses OJ_BUNDLE_PRAGMA marker to distinguish
from user-written comments.

Fixes #438

Author: adamant-pwn

onlinejudge_verify/languages/cplusplus_bundle.py

@@ -184,8 +184,17 @@ def _get_uncommented_code(path: pathlib.Path, *, iquotes_options: Tuple[str, ...
         if compiler == 'g++':
             raise BundleError(f'A fake g++ is detected. Please install the GNU C++ compiler.: {compiler}')
         raise BundleError(f"It's not g++. Please specify g++ with $CXX envvar.: {compiler}")
-    command = [compiler, '-x', 'c++', *iquotes_options, '-fpreprocessed', '-dD', '-E', str(path)]
-    return subprocess.check_output(command)
+
+    # Comment out #pragma GCC target() before preprocessing to avoid GCC emitting extra macros
+    with open(str(path), 'rb') as f:
+        source = f.read()
+    source = re.sub(rb'^(\s*)#\s*pragma\s+GCC\s+target\s*\(', rb'\1/* OJ_BUNDLE_PRAGMA */ // #pragma GCC target(', source, flags=re.MULTILINE)
+
+    command = [compiler, '-x', 'c++', *iquotes_options, '-fpreprocessed', '-dD', '-E', '-']
+    result = subprocess.check_output(command, input=source)
+
+    # Uncomment pragmas in output
+    return re.sub(rb'^(\s*)/\*\s*OJ_BUNDLE_PRAGMA\s*\*/\s*//\s*#\s*pragma\s+GCC\s+target\s*\(', rb'\1#pragma GCC target(', result, flags=re.MULTILINE)
 
 
 def get_uncommented_code(path: pathlib.Path, *, iquotes: List[pathlib.Path], compiler: str) -> bytes: