Use CMAKE_INSTALL_*DIRs

Author: otegami

.github/workflows/autotools.yml

@@ -194,9 +194,12 @@ jobs:
       - name: Build msgpack-c
         run: |
           cd msgpack-c
-          cmake -S . -B ../msgpack-c.build -DCMAKE_INSTALL_PREFIX=/usr/local
+          cmake -S . -B ../msgpack-c.build -DCMAKE_INSTALL_PREFIX=/usr/local \
+                                           -DCMAKE_INSTALL_LIBDIR=lib64 \
+                                           -DCMAKE_INSTALL_INCLUDEDIR=include64
           cmake --build ../msgpack-c.build
           sudo cmake --install ../msgpack-c.build
+          export PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig:$PKG_CONFIG_PATH
       - name: Prepare ccache
         run: |
           echo "CCACHE_DIR=${PWD}/ccache" >> ${GITHUB_ENV}