CI: Test building without C++ runtime on GCC/Clang.

.github/workflows/build.yml

@@ -288,6 +288,14 @@ jobs:
         echo '#include "examples/example_null/main.cpp"'                                      >> example_single_file.cpp
         g++ -I. -Wall -Wformat -o example_single_file example_single_file.cpp
 
+    - name: Build example_null (without c++ runtime, Clang)
+      run: |
+        echo '#define IMGUI_IMPLEMENTATION'                    >  example_single_file.cpp
+        echo '#define IMGUI_DISABLE_DEMO_WINDOWS'              >> example_single_file.cpp
+        echo '#include "misc/single_file/imgui_single_file.h"' >> example_single_file.cpp
+        echo '#include "examples/example_null/main.cpp"'       >> example_single_file.cpp
+        clang++ -I. -Wall -Wformat -nodefaultlibs -fno-rtti -fno-exceptions -fno-threadsafe-statics -lc -lm -o example_single_file example_single_file.cpp
+
     - name: Build example_glfw_opengl2
       run: make -C examples/example_glfw_opengl2
 
@@ -324,6 +332,13 @@ jobs:
         echo '#include "examples/example_null/main.cpp"'       >> example_single_file.cpp
         clang++ -I. -Wall -Wformat -o example_single_file example_single_file.cpp
 
+    - name: Build example_null (without c++ runtime)
+      run: |
+        echo '#define IMGUI_IMPLEMENTATION'                    >  example_single_file.cpp
+        echo '#include "misc/single_file/imgui_single_file.h"' >> example_single_file.cpp
+        echo '#include "examples/example_null/main.cpp"'       >> example_single_file.cpp
+        clang++ -I. -Wall -Wformat -nodefaultlibs -fno-rtti -fno-exceptions -fno-threadsafe-statics -lc -lm -o example_single_file example_single_file.cpp
+
     - name: Build example_glfw_opengl2
       run: make -C examples/example_glfw_opengl2
 

docs/CHANGELOG.txt

@@ -56,6 +56,9 @@ Other Changes:
   BeginMenu()/EndMenu() or BeginPopup/EndPopup(). (#3223, #1207) [@rokups]
 - Drag and Drop: Fixed unintended fallback "..." tooltip display during drag operation when
   drag source uses _SourceNoPreviewTooltip flags. (#3160) [@rokups]
+- CI: Added CI test to verify we're never accidentally dragging libstdc++ (on some compiler setups,
+  static constructors for non-pod data seems to drag in libstdc++ due to thread-safety concerns).
+  Fixed a static contructor which led to this dependency on some compiler setups (unclear which).
 - Backends: Win32: Support for #define NOGDI, won't try to call GetDeviceCaps(). (#3137, #2327)
 - Backends: Win32: Fix _WIN32_WINNT < 0x0600 (MinGW defaults to 0x502 == Windows 2003). (#3183)
 - Backends: SDL: Report a zero display-size when window is minimized, consistent with other backends,