Backport managarm/gcc@61271f4 into clang compat patch

.github/workflows/run.yml

@@ -37,6 +37,9 @@ jobs:
           mv toolchain/include/c++/* ${{matrix.target_arch}}/include
           cp -rp ${{matrix.target_arch}}/include/${{matrix.target_arch}}-elf/* ${{matrix.target_arch}}/include/
           rm -rf ${{matrix.target_arch}}/include/${{matrix.target_arch}}-elf
+          for f in patches/*; do \
+            ( cd ${{matrix.target_arch}} && patch -p0 <../$f ); \
+          done
 
       - name: Push
         run: |

patches/clang-compat.patch

@@ -0,0 +1,33 @@
+diff '--color=auto' -urN include/atomic include-patched/atomic
+--- include/atomic	2024-09-22 05:50:48.546122362 +0200
++++ include-patched/atomic	2024-09-22 05:59:15.115746337 +0200
+@@ -1650,6 +1650,7 @@
+       using __atomic_float<double>::operator=;
+     };
+
++#if !(defined(__clang__) && !__STDC_HOSTED__) // clang in kernel context
+   template<>
+     struct atomic<long double> : __atomic_float<long double>
+     {
+@@ -1664,6 +1665,7 @@
+
+       using __atomic_float<long double>::operator=;
+     };
++#endif
+
+ #ifdef __STDCPP_FLOAT16_T__
+   template<>
+diff '--color=auto' -urN include/bits/stl_algobase.h include-patched/bits/stl_algobase.h
+--- include/bits/stl_algobase.h	2024-09-22 05:50:48.546122362 +0200
++++ include-patched/bits/stl_algobase.h	2024-09-22 05:58:04.080067281 +0200
+@@ -1072,8 +1072,10 @@
+   __size_to_integer(float __n) { return (long long)__n; }
+   inline _GLIBCXX_CONSTEXPR long long
+   __size_to_integer(double __n) { return (long long)__n; }
++#if !(defined(__clang__) && !__STDC_HOSTED__) // clang in kernel context
+   inline _GLIBCXX_CONSTEXPR long long
+   __size_to_integer(long double __n) { return (long long)__n; }
++#endif
+ #if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
+   __extension__ inline _GLIBCXX_CONSTEXPR long long
+   __size_to_integer(__float128 __n) { return (long long)__n; }