sci-ml/pytorch: fix compilation of HIP extensions

Noticed in sci-ml/torchvision:
1) compilation failed on multilib (Gentoo-related)
2) compilation failed with Clang-libc++ (patch should be in upstream)

Bug: https://bugs.gentoo.org/959589
Signed-off-by: Sv. Lockal <lockalsash@gmail.com>
Part-of: https://github.com/gentoo/gentoo/pull/42891
Signed-off-by: Alfredo Tupone <tupone@gentoo.org>

sci-ml/pytorch/files/pytorch-2.7.1-cpp-extension-libcxx.patch

@@ -0,0 +1,22 @@
+Fixes parsing of Clang versions like 20.1.7+libcxx
+
+Upstream bug: https://github.com/pytorch/pytorch/issues/157665
+--- a/torch/utils/cpp_extension.py
++++ b/torch/utils/cpp_extension.py
+@@ -434,13 +434,12 @@ def get_compiler_abi_compatibility_and_version(compiler) -> tuple[bool, TorchVer
+     try:
+         if IS_LINUX:
+             minimum_required_version = MINIMUM_GCC_VERSION
+-            versionstr = subprocess.check_output([compiler, '-dumpfullversion', '-dumpversion'])
+-            version = versionstr.decode(*SUBPROCESS_DECODE_ARGS).strip().split('.')
++            compiler_info = subprocess.check_output([compiler, '-dumpfullversion', '-dumpversion'])
+         else:
+             minimum_required_version = MINIMUM_MSVC_VERSION
+             compiler_info = subprocess.check_output(compiler, stderr=subprocess.STDOUT)
+-            match = re.search(r'(\d+)\.(\d+)\.(\d+)', compiler_info.decode(*SUBPROCESS_DECODE_ARGS).strip())
+-            version = ['0', '0', '0'] if match is None else list(match.groups())
++        match = re.search(r'(\d+)\.(\d+)\.(\d+)', compiler_info.decode(*SUBPROCESS_DECODE_ARGS).strip())
++        version = ['0', '0', '0'] if match is None else list(match.groups())
+     except Exception:
+         _, error, _ = sys.exc_info()
+         warnings.warn(f'Error checking compiler version for {compiler}: {error}')

sci-ml/pytorch/files/pytorch-2.7.1-cpp-extension-multilib.patch

@@ -0,0 +1,25 @@
+Fixes multilib (%LIB_DIR% should be replaced in ebuild)
+--- a/torch/utils/cpp_extension.py
++++ b/torch/utils/cpp_extension.py
+@@ -1478,10 +1477,10 @@ def library_paths(device_type: str = "cpu") -> list[str]:
+     paths = [TORCH_LIB_PATH]
+ 
+     if device_type == "cuda" and IS_HIP_EXTENSION:
+-        lib_dir = 'lib'
++        lib_dir = '%LIB_DIR%'
+         paths.append(_join_rocm_home(lib_dir))
+         if HIP_HOME is not None:
+-            paths.append(os.path.join(HIP_HOME, 'lib'))
++            paths.append(os.path.join(HIP_HOME, '%LIB_DIR%'))
+     elif device_type == "cuda":
+         if IS_WINDOWS:
+             lib_dir = os.path.join('lib', 'x64')
+@@ -2295,7 +2294,7 @@ def _prepare_ldflags(extra_ldflags, with_cuda, verbose, is_standalone):
+             if CUDNN_HOME is not None:
+                 extra_ldflags.append(f'-L{os.path.join(CUDNN_HOME, "lib64")}')
+         elif IS_HIP_EXTENSION:
+-            extra_ldflags.append(f'-L{_join_rocm_home("lib")}')
++            extra_ldflags.append(f'-L{_join_rocm_home("%LIB_DIR%")}')
+             extra_ldflags.append('-lamdhip64')
+     return extra_ldflags
+ 

sci-ml/pytorch/pytorch-2.7.1-r1.ebuild

@@ -34,19 +34,25 @@ DEPEND="${RDEPEND}
 	')
 "
 
+PATCHES=(
+	"${FILESDIR}"/${PN}-2.6.0-dontbuildagain.patch
+	"${FILESDIR}"/${PN}-2.7.1-cpp-extension-libcxx.patch
+	"${FILESDIR}"/${PN}-2.7.1-cpp-extension-multilib.patch
+)
+
 src_prepare() {
-	eapply "${FILESDIR}"/${PN}-2.6.0-dontbuildagain.patch
+	# Replace placeholders added by cpp-extension.patch
+	sed -e "s|%LIB_DIR%|$(get_libdir)|g" \
+		-i torch/utils/cpp_extension.py || die
 
 	# Set build dir for pytorch's setup
-	sed -i \
-		-e "/BUILD_DIR/s|build|/var/lib/caffe2/|" \
-		tools/setup_helpers/env.py \
-		|| die
+	sed -e "/BUILD_DIR/s|build|/var/lib/caffe2/|" \
+		-i tools/setup_helpers/env.py || die
+
 	# Drop legacy from pyproject.toml
-	sed -i \
-		-e "/build-backend/s|:__legacy__||" \
-		pyproject.toml \
-		|| die
+	sed -e "/build-backend/s|:__legacy__||" \
+		-i pyproject.toml || die
+
 	distutils-r1_src_prepare
 
 	# Get object file from caffe2