Fix compiler used by "Build and tests" action (#292)

* Make sure the build workflow actually uses the chosen compiler.

Also clean up the repetitive nature of the workflow by defining the word
size as another matrix axis and making iso the default target.

Signed-off-by: Kimon Hoffmann <Kimon.Hoffmann@lawo.com>

* Disabled clang as a compiler alongside gcc.

The state of the current makefiles/source code is not compatible with
clang, so it makes no sense to try to build with it.

Signed-off-by: Kimon Hoffmann <Kimon.Hoffmann@lawo.com>

.github/workflows/Linux.yml

@@ -13,14 +13,15 @@ on:
 
 jobs:
   build:
-    name: ${{ matrix.os }} ${{ matrix.compiler }}
+    name: ${{ matrix.os }} ${{ matrix.compiler }} ${{ matrix.wordsize }}
     runs-on: ${{ matrix.os }}
 
     strategy:
       fail-fast: false
       matrix:
-        compiler: [gcc, clang]
+        compiler: [gcc]
         os: [ubuntu-20.04, ubuntu-22.04]
+        wordsize: [32, 64]
 
     steps:
       - uses: actions/checkout@v3
@@ -30,34 +31,10 @@ jobs:
       - name: Install Linux Dependencies
         run: sudo apt-get install build-essential gcc-multilib clang libc6-dev-i386-cross dosfstools mtools xorriso -y
 
-      - name: Make all build32
+      - name: Clean up
-        env:
+        working-directory: ./build${{matrix.wordsize}}
-          C: ${{matrix.compiler}}
-        working-directory: ./build32
-        run: make -j 2 all
-
-      - name: Make clean build32
-        working-directory: ./build32
         run: make clean
 
-      - name: Make all build64
+      - name: Build
-        env:
+        working-directory: ./build${{matrix.wordsize}}
-          C: ${{matrix.compiler}}
+        run: make -j 2 CC="${{matrix.compiler}}" iso
-        working-directory: ./build64
-        run: make -j 2 all
-
-      - name: Make clean build64
-        working-directory: ./build64
-        run: make clean
-
-      - name: Make iso build32
-        env:
-          C: ${{matrix.compiler}}
-        working-directory: ./build32
-        run: make -j 2 iso
-
-      - name: Make iso build64
-        env:
-          C: ${{matrix.compiler}}
-        working-directory: ./build64
-        run: make -j 2 iso