Clarify the build names

.github/workflows/c-cpp.yml

@@ -17,8 +17,8 @@ jobs:
 
     strategy:
       matrix:
-        dev-build: ['y', 'n']
-        new-dynarec: ['y', 'n']
+        dev-build: ['DEV_BUILD=y', 'DEV_BUILD=n']
+        new-dynarec: ['NEW_DYNAREC=y', 'NEW_DYNAREC=n']
 
     steps:
     - uses: msys2/setup-msys2@v1
@@ -28,5 +28,5 @@ jobs:
         install: 'make mingw-w64-i686-toolchain mingw-w64-i686-openal mingw-w64-i686-freetype mingw-w64-i686-SDL2 mingw-w64-i686-zlib mingw-w64-i686-libpng mingw-w64-i686-libvncserver'
     - uses: actions/checkout@v2
     - name: make
-      run: make -fwin/makefile.mingw DEV_BUILD=${{ matrix.dev-build }} NEW_DYNAREC=${{ matrix.new-dynarec }} VNC=n
+      run: make -fwin/makefile.mingw ${{ matrix.dev-build }} ${{ matrix.new-dynarec }} VNC=n
       working-directory: ./src