CI: Amend e3cb016.

.github/workflows/build.yml

@@ -324,6 +324,18 @@ jobs:
         EOF
         g++ -I. -std=c++11 -Wall -Wformat -o example_single_file example_single_file.cpp
 
+    - name: Build example_null (with C++26)
+      run: |
+        cat > example_single_file.cpp <<'EOF'
+
+        #define IMGUI_DISABLE_OBSOLETE_KEYIO
+        #define IMGUI_IMPLEMENTATION
+        #include "misc/single_file/imgui_single_file.h"
+        #include "examples/example_null/main.cpp"
+
+        EOF
+        g++ -I. -std=c++26 -Wall -Wformat -o example_single_file example_single_file.cpp
+
     - name: Build example_null (with IMGUI_DISABLE_DEMO_WINDOWS and IMGUI_DISABLE_DEBUG_TOOLS)
       run: |
         cat > example_single_file.cpp <<'EOF'
@@ -433,7 +445,7 @@ jobs:
         EOF
         clang++ -I. -std=c++11 -Wall -Wformat -o example_single_file example_single_file.cpp
 
-    - name: Build example_null (single file build, c++26)
+    - name: Build example_null (single file build, c++20)
       run: |
         cat > example_single_file.cpp <<'EOF'
 
@@ -442,7 +454,7 @@ jobs:
         #include "examples/example_null/main.cpp"
 
         EOF
-        clang++ -I. -std=c++26 -Wall -Wformat -o example_single_file example_single_file.cpp
+        clang++ -I. -std=c++20 -Wall -Wformat -o example_single_file example_single_file.cpp
 
     - name: Build example_null (without c++ runtime)
       run: |