Fix & improvements in Linux Build workflow (#686)

* Fix of Linux Build workflow: add missing apt-get update

Change-Id: I69cd1693b2ad5405574affe5b85e5c4c9c76e278
Signed-off-by: Jan Matyas <matyas@codasip.com>

* Minor improvements in Linux Build workflow

- Use parallel build (use -j for make)
- Check that the resulting OpenOCD executable can actually be launched (call openocd --version)

Change-Id: I6b8c56688a39cae436986954fbd517082dc8160d
Signed-off-by: Jan Matyas <matyas@codasip.com>

.github/workflows/linux-build.yml

@@ -12,11 +12,15 @@ jobs:
     steps:
       - name: Checkout Code
         uses: actions/checkout@v2
-      - run: sudo apt-get install clang gcc-multilib
+      - name: Install required packages (apt-get)
+        run: |
+          sudo apt-get update
+          sudo apt-get install clang gcc-multilib
       - run: ./bootstrap
       - run: ./configure --enable-remote-bitbang --enable-jtag_vpi --disable-target64
-      - run: make
+      - run: make -j`nproc`
       - run: file src/openocd | grep 32-bit
+      - run: src/openocd --version
 
 
   # 64-bit, gcc
@@ -28,8 +32,12 @@ jobs:
     steps:
       - name: Checkout Code
         uses: actions/checkout@v2
-      - run: sudo apt-get install libusb-1.0-0 libusb-1.0-0-dev
+      - name: Install required packages (apt-get)
+        run: |
+          sudo apt-get update
+          sudo apt-get install libusb-1.0-0 libusb-1.0-0-dev
       - run: ./bootstrap
       - run: ./configure --enable-remote-bitbang --enable-jtag_vpi --enable-ftdi-oscan1
-      - run: make
+      - run: make -j`nproc`
       - run: file src/openocd | grep 64-bit
+      - run: src/openocd --version