Avoid use of cmd.exe in Travis

.travis.yml

@@ -26,13 +26,14 @@ install:
       export PATH=~/Library/Python/3.7/bin:$PATH
       pip3 install --user ninja cmake
     else
+      pipenv global 3.6
       pip install --user ninja cmake
     fi
 script:
   - |
     if [[ $TRAVIS_OS_NAME == 'windows' ]]; then
-      cmd.exe /C '"C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Auxiliary\Build\vcvarsall.bat" amd64 && cmake -Bbuild -G Ninja -DCMAKE_BUILD_TYPE=Release -DARGPARSE_BUILD_TESTS=ON && ninja -C build'
+      tools/build.bat
     else
-      cmake -Bbuild -G Ninja -DCMAKE_BUILD_TYPE=Release -DARGPARSE_BUILD_TESTS=ON && ninja -C build
+      sh tools/build.sh
     fi
   - ./build/test/tests

test/CMakeLists.txt

@@ -1,5 +1,4 @@
 cmake_minimum_required(VERSION 3.6)
-project(ARGPARSE)
 
 if(MSVC)
   # Force to always compile with W4

tools/build.bat

@@ -0,0 +1,4 @@
+call "C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Auxiliary\Build\vcvars64.bat"
+
+cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DARGPARSE_BUILD_TESTS=ON
+ninja -C build

tools/build.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DARGPARSE_BUILD_TESTS=ON
+ninja -C build