[main] Reduce deps for clang on Linux and set sysroot (#252)

automerged PR by conda-forge/automerge-action

recipe/get_cpu_triplet.sh

@@ -0,0 +1,16 @@
+get_triplet() {
+  local CPU_ARCH
+  if [[ "$1" == "linux-64" ]]; then
+    CPU_ARCH="x86_64"
+  elif [[ "$1" == "linux-ppc64le" ]]; then
+    CPU_ARCH="powerpc64le"
+  elif [[ "$1" == "linux-aarch64" ]]; then
+    CPU_ARCH="aarch64"
+  elif [[ "$1" == "linux-s390x" ]]; then
+    CPU_ARCH="s390x"
+  else
+    echo "Unknown architecture"
+    exit 1
+  fi
+  echo $CPU_ARCH-conda-linux-gnu
+}

recipe/install_clang_symlinks.sh

@@ -5,3 +5,11 @@ maj_version="${PKG_VERSION%%.*}"
 ln -s "${PREFIX}/bin/clang-${maj_version}" "${PREFIX}/bin/clang-cl"
 ln -s "${PREFIX}/bin/clang-${maj_version}" "${PREFIX}/bin/clang-cpp"
 ln -s "${PREFIX}/bin/clang-${maj_version}" "${PREFIX}/bin/clang"
+
+if [[ "$target_platform" == "linux-"* ]]; then
+  source ${RECIPE_DIR}/get_cpu_triplet.sh
+  CHOST=$(get_triplet $target_platform)
+  ln -s "${PREFIX}/bin/clang-${maj_version}" "${PREFIX}/bin/${CHOST}-clang"
+  # for background, see comment in install_clangxx.sh
+  echo "--sysroot ${PREFIX}/${CHOST}/sysroot" >> ${PREFIX}/bin/${CHOST}-clang.cfg
+fi

recipe/install_clangxx.sh

@@ -1,8 +1,20 @@
 #!/bin/bash
 
 ln -s $PREFIX/bin/clang  $PREFIX/bin/clang++
-ln -s $PREFIX/bin/clang  $PREFIX/bin/$HOST-clang++
 
 if [[ "$variant" == "hcc" ]]; then
   ln -s $PREFIX/bin/clang++  $PREFIX/bin/hcc
 fi
+
+if [[ "$target_platform" == "linux-"* ]]; then
+  source ${RECIPE_DIR}/get_cpu_triplet.sh
+  CHOST=$(get_triplet $target_platform)
+  ln -s "${PREFIX}/bin/clang++" "${PREFIX}/bin/${CHOST}-clang++"
+  # In the cross compiling case, we set CONDA_BUILD_SYSROOT to host platform
+  # which makes compiling for build platform not work correctly.
+  # The following overrides CONDA_BUILD_SYSROOT, so that a clang for a given
+  # CHOST will always use the appropriate sysroot. In particular, this means
+  # that a clang in the build environment will work correctly for its native
+  # architecture also in cross compilation scenarios.
+  echo "--sysroot ${PREFIX}/${CHOST}/sysroot" >> ${PREFIX}/bin/${CHOST}-clang++.cfg
+fi

recipe/meta.yaml

@@ -1,6 +1,6 @@
 {% set version = "17.0.4" %}
 {% set major_version = version.split(".")[0] %}
-{% set build_number = 0 %}
+{% set build_number = 1 %}
 
 {% set minor_aware_ext = major_version %}
 {% if version.split(".")[1] | int > 0 %}
@@ -392,7 +392,6 @@ outputs:
         - zstd     # [unix]
     requirements:
       host:
-        - gcc_impl_{{ target_platform }}  # [linux]
         - {{ pin_subpackage("clang-" ~ major_version, exact=True) }}
         # Use the same requirements as the top-level requirements
         - libcxx {{ cxx_compiler_version }}  # [osx]
@@ -401,7 +400,9 @@ outputs:
         - zlib
         - zstd
       run:
-        - gcc_impl_{{ target_platform }}  # [linux]
+        - binutils_impl_{{ target_platform }}  # [linux]
+        - sysroot_{{ target_platform }}        # [linux]
+        - libgcc-devel_{{ target_platform }}   # [linux]
         - {{ pin_subpackage("clang-" ~ major_version, exact=True) }}
     test:
       commands:
@@ -431,6 +432,7 @@ outputs:
         - zlib
         - zstd
       run:
+        - libstdcxx-devel_{{ target_platform }}  # [linux]
         - {{ pin_subpackage("clang", exact=True) }}
     test:
       requires: