fix low volume due to wrong init of audioDAC_data

add support for mixing stereo to mono through dsp_processor (fixes #106)
add sdkconfigs to github action workflow
suppress warnings from flac git submodule
remove unused variable and address some compiler warnings
remove some dead code

Signed-off-by: Karl Osterseher <karl_osterseher@gmx.at>

.github/workflows/build.yml

@@ -4,9 +4,10 @@ on: push
 
 jobs:
   build:
-
+    strategy:
+      matrix:
+        sdkconfig: [sdkconfig_TAS5805M, sdkconfig_PCM5102A, sdkconfig_lyrat_v4.3, sdkconfig_adau1961]
     runs-on: ubuntu-latest
-
     steps:
     - name: Checkout repo
       uses: actions/checkout@v2
@@ -18,10 +19,10 @@ jobs:
       uses: espressif/esp-idf-ci-action@v1.1.0
       with:
         # Relative path under $GITHUB_WORKSPACE to place the repository
-        #path: # optional, default is 
+        #path: # optional, default is
         # Version of ESP-IDF docker image to use
-        esp_idf_version: v5.1.1 # optional, default is latest
+        esp_idf_version: v5.1.5 # optional, default is latest
         # ESP32 variant to build for
         target: esp32 # optional, default is esp32
         # Command to run inside the docker container (default: builds the project)
-        command: idf.py build -DSDKCONFIG=./sdkconfig_lyrat_v4.3 # optional, default is idf.py build
+        command: idf.py build -DSDKCONFIG=${{ matrix.sdkconfig }} # optional, default is idf.py build