let's actually check that

.github/workflows/dos-djgpp.yml

@@ -42,7 +42,7 @@ jobs:
       - name: Setup build environment
         run: |
           sudo apt -y update
-          sudo apt -y install build-essential cmake wget 7zip git flex libfl-dev nasm libslang2-dev pkg-config libslang2-modules gcc-multilib dosbox
+          sudo apt -y install build-essential cmake wget 7zip git flex libfl-dev nasm libslang2-dev pkg-config libslang2-modules gcc-multilib dosbox tree
 
       - name: Download and Setup DJGPP Toolchain
         run: |
@@ -50,6 +50,7 @@ jobs:
           wget https://github.com/andrewwutw/build-djgpp/releases/download/v3.4/djgpp-linux64-gcc1220.tar.bz2
           tar xjf djgpp-linux64-gcc1220.tar.bz2
           cd ${{ github.workspace }}/djgpp
+          tree . -S
           git clone https://github.com/UMSKT/Watt-32.git watt32
           cd watt32/util
           make clean && make linux
@@ -84,12 +85,18 @@ jobs:
           path: |
             ${{ github.workspace }}/djgpp
           key: openssl-3.1.2-${{ hashFiles('**/CMakeLists.txt') }}
-
+          
+      - name: Download stub
+        run: |
+          wget https://web.archive.org/web/20250308092209/https://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/util/system/cwsdpmi/csdpmi7b.zip -O CSDPMI7B.ZIP
+          mkdir /home/runner/dpmibin
+          7z e CSDPMI7B.ZIP bin/CWSDSTUB.EXE -o/home/runner/dpmibin
+          
       - name: Build
         run: |
           source ${{ github.workspace }}/djgpp/setenv
           pushd build
-          cmake ../ -D DJGPP_WATT32=${WATT_ROOT}/lib/libwatt.a -D CMAKE_FIND_ROOT_PATH=${CMAKE_FIND_ROOT_PATH}
+          cmake ../ -D DJGPP_WATT32=${WATT_ROOT}/lib/libwatt.a -D CMAKE_FIND_ROOT_PATH=${CMAKE_FIND_ROOT_PATH} -D CWSDSTUB_LOCATION=/home/runner/dpmibin/CWSDSTUB.EXE -D DJGPP_BIN_LOCATION=/home/runner/work/UMSKT/UMSKT/djgpp/i586-pc-msdosdjgpp/bin
           make
 
       - name: Setup DOSBox test environment
@@ -97,7 +104,7 @@ jobs:
           mkdir -p dosbox_test
           cp build/umskt.exe dosbox_test/
           # Download DPMI server directly
-          wget https://github.com/UMSKT/winactiontest/raw/refs/heads/main/CWSDPMI.EXE -O dosbox_test/CWSDPMI.EXE
+          # wget https://github.com/UMSKT/winactiontest/raw/refs/heads/main/CWSDPMI.EXE -O dosbox_test/CWSDPMI.EXE
           # Create test batch file
           cat > dosbox_test/test.bat << EOL
           @echo off
@@ -119,6 +126,7 @@ jobs:
           [sdl]
           nosound=true
           [cpu]
+          cputype=386
           core=dynamic
           cycles=max
           [autoexec]

CMakeLists.txt

@@ -108,7 +108,8 @@ IF(DJGPP_WATT32)
     # Maximum compatibility flags for DOS/NTVDM
     SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=i386 -mtune=i386 -mno-sse -mno-sse2 -mno-mmx -mno-3dnow -mno-ssse3 -mno-sse3 -mno-sse4 -mno-sse4.1 -mno-sse4.2 -mno-avx -mno-avx2 -mno-fma -mno-fma4")
     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=i386 -mtune=i386 -mno-sse -mno-sse2 -mno-mmx -mno-3dnow -mno-ssse3 -mno-sse3 -mno-sse4 -mno-sse4.1 -mno-sse4.2 -mno-avx -mno-avx2 -mno-fma -mno-fma4")
-    MESSAGE(STATUS "[UMSKT] Using i386 target for DOS DGJPP")
+    
+    MESSAGE(STATUS "[UMSKT] Using i386 target for DOS DGJPP with stub: ${CWSDSTUB_LOCATION}")
 ENDIF()
 
 ##if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
@@ -273,4 +274,21 @@ ELSE()
         GET_FILENAME_COMPONENT(OPENSSL_CRYPTO_LIBRARY_FILENAME ${OPENSSL_CRYPTO_LIBRARY} NAME)
         CONFIGURE_FILE(${OPENSSL_CRYPTO_LIBRARY} "${CMAKE_CURRENT_BINARY_DIR}/${OPENSSL_CRYPTO_LIBRARY_FILENAME}" COPYONLY)
     ENDIF()
+
+    IF (DJGPP_WATT32)
+        message(STATUS "[UMSKT] Configuring DJGPP post-build commands")
+        # Set .exe suffix for DJGPP builds
+        set_target_properties(umskt PROPERTIES SUFFIX ".exe")
+        add_custom_command(TARGET umskt POST_BUILD 
+            # Convert exe to coff, removing the default stub
+            COMMAND ${DJGPP_BIN_LOCATION}/exe2coff $<TARGET_FILE:umskt>
+            # Concatenate CWSDSTUB with the COFF file
+            COMMAND ${CMAKE_COMMAND} -E cat ${CWSDSTUB_LOCATION} $<TARGET_FILE_DIR:umskt>/umskt > $<TARGET_FILE:umskt>
+            # Clean up the COFF file
+            COMMAND ${CMAKE_COMMAND} -E rm $<TARGET_FILE_DIR:umskt>/umskt
+        )
+        message(STATUS "[UMSKT] STUBIFY_LOCATION set to: ${STUBIFY_LOCATION}")
+        message(STATUS "[UMSKT] CWSDSTUB_LOCATION set to: ${CWSDSTUB_LOCATION}")
+        message(STATUS "[UMSKT] DJGPP_BIN_LOCATION set to: ${DJGPP_BIN_LOCATION}")
+    ENDIF()
 ENDIF()