Sync from upstream.

.github/workflows/ci.yml

@@ -22,6 +22,7 @@ jobs:
 
           - lib: filesystem
             bopts: install
+            copts: -DCMAKE_CXX_STANDARD=11
             os: macos-latest
 
           # --layout=versioned
@@ -32,6 +33,7 @@ jobs:
 
           - lib: filesystem
             bopts: --layout=versioned install
+            copts: -DCMAKE_CXX_STANDARD=11
             os: macos-latest
 
           # --layout=tagged
@@ -42,6 +44,7 @@ jobs:
 
           - lib: filesystem
             bopts: --layout=tagged install
+            copts: -DCMAKE_CXX_STANDARD=11
             os: macos-latest
 
           # build with clang++, use with g++
@@ -164,7 +167,7 @@ jobs:
 
           - lib: filesystem
             bopts: stage
-            copts: -DUSE_STAGED_BOOST=ON
+            copts: -DUSE_STAGED_BOOST=ON -DCMAKE_CXX_STANDARD=11
             os: macos-latest
 
           - lib: filesystem
@@ -352,7 +355,7 @@ jobs:
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install packages
         if: matrix.install
@@ -549,7 +552,7 @@ jobs:
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup Boost
         shell: cmd

test/BoostVersion.cmake

@@ -1 +1 @@
-set(BOOST_VERSION 1.85.0)
+set(BOOST_VERSION 1.86.0)