Rework as esp-idf component

See boostorg/boost-ci#166

.github/workflows/ci.yml

@@ -131,20 +131,23 @@ jobs:
             fi
             git config --global pack.threads 0
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           # For coverage builds fetch the whole history, else only 1 commit using a 'fake ternary'
           fetch-depth: ${{ matrix.coverage && '0' || '1' }}
 
       - name: Cache ccache
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         if: env.B2_USE_CCACHE
         with:
           path: ~/.ccache
-          key: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}
+          key: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-${{github.sha}}
+          restore-keys: |
+            ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-
+            ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}
 
       - name: Fetch Boost.CI
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: boostorg/boost-ci
           ref: master

CMakeLists.txt

@@ -2,6 +2,8 @@
 # Distributed under the Boost Software License, Version 1.0.
 # See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
 
+if(NOT DEFINED IDF_TARGET)
+
 cmake_minimum_required( VERSION 3.5...3.20 )
 project( boost_mpl VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX )
 
@@ -20,3 +22,24 @@ target_link_libraries( boost_mpl
         Boost::type_traits
         Boost::utility
 )
+
+else()
+
+FILE(GLOB_RECURSE headers include/*.h include/*.hpp)
+
+idf_component_register(
+    SRCS
+        ${headers}
+    INCLUDE_DIRS
+        include
+    REQUIRES
+        boost_config
+        boost_core
+        boost_predef
+        boost_preprocessor
+        boost_static_assert
+        boost_type_traits
+        boost_utility
+)
+
+endif()