Build: Install shellcheck manually

.travis.yml

@@ -9,12 +9,17 @@ matrix:
   include:
   - os: linux
     name: "Shellcheck on Linux"
-    addons:
-      apt:
-        packages:
-        - shellcheck
 
     script:
+      # Travis shellcheck is borked
+      - file="shellcheck-v0.7.1"
+      - suf=".linux.x86_64.tar.xz"
+      - curl -LO "https://github.com/koalaman/shellcheck/releases/download/v0.7.1/${file}${suf}" || exit 1
+      - sum=$(shasum -a 256 "${file}${suf}" | cut -f1 -d' ')
+      - expsum="64f17152d96d7ec261ad3086ed42d18232fcb65148b44571b564d688269d36c8"
+      - if [ "$sum" != "$expsum" ]; then echo "Invalid checksum $sum" ; exit 1 ; fi
+      - tar -xf "${file}${suf}" || exit 1
+      - export PATH="$(pwd)/${file}:$PATH"
       # Check Parent Dir (Change "*.tool" to "*.{sh,tool}" as required if needed later)
       - shellcheck ./*.tool
       # Check Sub Dirs (Change "*.tool" to "*.{sh,tool}" as required if needed later)
@@ -53,13 +58,14 @@ matrix:
 
     script:
     - export PYTHON_COMMAND=python3 # Something is broken in Travis CI environment, it asks for python3.7.
-    - llvmfile="clang+llvm-9.0.1-x86_64-linux-gnu-ubuntu-16.04"
-    - curl -LO "https://github.com/llvm/llvm-project/releases/download/llvmorg-9.0.1/${llvmfile}.tar.xz" || exit 1
-    - llvmsum=$(shasum -a 256 "${llvmfile}.tar.xz" | cut -f1 -d' ')
-    - llvmexpsum="1af280e96fec62acf5f3bb525e36baafe09f95f940dc9806e22809a83dfff4f8"
-    - if [ "$llvmsum" != "$llvmexpsum" ]; then echo "Invalid LLVM checksum $llvmsum" ; exit 1 ; fi
-    - tar -xf "${llvmfile}.tar.xz" || exit 1
-    - export PATH="$(pwd)/${llvmfile}/bin:$PATH"
+    - file="clang+llvm-9.0.1-x86_64-linux-gnu-ubuntu-16.04"
+    - suf=".tar.xz"
+    - curl -LO "https://github.com/llvm/llvm-project/releases/download/llvmorg-9.0.1/${file}${suf}" || exit 1
+    - sum=$(shasum -a 256 "${file}${suf}" | cut -f1 -d' ')
+    - expsum="1af280e96fec62acf5f3bb525e36baafe09f95f940dc9806e22809a83dfff4f8"
+    - if [ "$sum" != "$expsum" ]; then echo "Invalid checksum $sum" ; exit 1 ; fi
+    - tar -xf "${file}${suf}" || exit 1
+    - export PATH="$(pwd)/${file}/bin:$PATH"
     - "./macbuild.tool"
 
   - os: linux