CI: improve logging for configure, build and install steps

* Line buffering for stdout and stderr to better preserve log order
 * Full log now contains both stdout and stderr to keep errors in context

.github/workflows/actions/linux/build/action.yml

@@ -46,7 +46,8 @@ runs:
       id: build
       shell: bash
       run: |
-        cmake --build ${{ inputs.builddir }} -j$(nproc) ${{ inputs.extraParameters }} > ${{ inputs.logFile }} 2> ${{ inputs.errorFile }}
+        (stdbuf -oL -eL cmake --build ${{ inputs.builddir }} -j$(nproc) ${{ inputs.extraParameters }}) \
+        2> >(tee -a ${{ inputs.errorFile }}) | tee -a ${{ inputs.logFile }}
     - name: Write report
       shell: bash
       if: always()
@@ -68,8 +69,3 @@ runs:
         echo '```' >> ${{ inputs.reportFile }}
         echo "</details>">> ${{ inputs.reportFile }}
         echo "" >> ${{ inputs.reportFile }}
-        # Print the Log to the console
-        cat ${{ inputs.errorFile }}
-        echo "::group::Build Log"
-        cat ${{ inputs.logFile }}
-        echo "::endgroup::"