Tidy up and fix lint errors in build scripts

I've tidied up the code in both of the build scripts used for *nix-like
systems, and the macOS/OSX specific build script helper.

This has been tested on Linux with no issues, but this PR will hopefully
indicate if the changes run without issues on macOS as well.

Signed-off-by: Dom Rodriguez <shymega@shymega.org.uk>

clean_build.sh

@@ -1,28 +1,52 @@
-#!/bin/sh
-cd "$(dirname $0)" || exit 1
+#!/bin/bash
+
+set -eu # we set this to catch errors and terminate
+
+cd "$(dirname "$0")" || exit 1
+
 # some environments have cmake v2 as 'cmake' and v3 as 'cmake3'
 # check for cmake3 first then fallback to just cmake
-B_CMAKE=`type cmake3 2>/dev/null`
-if [ $? -eq 0 ]; then
-    B_CMAKE=`echo $B_CMAKE | cut -d' ' -f3`
+
+if type cmake3 2>/dev/null; then
+    B_CMAKE=$(command -v "$(echo "$B_CMAKE" | cut -d' ' -f3)")
 else
-    B_CMAKE=cmake
+    B_CMAKE=$(command -v cmake)
 fi
+
 # default build configuration
 B_BUILD_TYPE=${B_BUILD_TYPE:-Debug}
-if [ "$(uname)" = "Darwin" ]; then
+
+if [ "$(uname -s)" = "Darwin" ]; then
     # OSX needs a lot of extra help, poor thing
     # run the osx_environment.sh script to fix paths
-    . ./osx_environment.sh
+    if [ -f "./osx_environment.sh" ]; then
+       . ./osx_environment.sh
+    fi
     B_CMAKE_FLAGS="-DCMAKE_OSX_SYSROOT=$(xcode-select --print-path)/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -DCMAKE_OSX_DEPLOYMENT_TARGET=10.9 $B_CMAKE_FLAGS"
 fi
+
 # allow local customizations to build environment
-[ -r ./build_env.sh ] && . ./build_env.sh
-B_CMAKE_FLAGS="-DCMAKE_BUILD_TYPE=$B_BUILD_TYPE $B_CMAKE_FLAGS"
+if [ -f "./build_env.sh" ]; then
+    . ./build_env.sh
+fi
+
+set +eu # disable this temporarily
+if [ -n "${B_CMAKE_FLAGS}" ]; then
+    B_CMAKE_FLAGS="-DCMAKE_BUILD_TYPE=$B_BUILD_TYPE ${B_CMAKE_FLAGS}"
+else
+    B_CMAKE_FLAGS="-DCMAKE_BUILD_TYPE=$B_BUILD_TYPE"
+fi
+set -eu # enable this
+
 rm -rf build
 mkdir build || exit 1
 cd build || exit 1
-echo Starting Barrier $B_BUILD_TYPE build...
-$B_CMAKE $B_CMAKE_FLAGS .. || exit 1
+
+echo "Starting Barrier build..."
+echo "Build type: ${B_BUILD_TYPE}"
+
+"$B_CMAKE" "$B_CMAKE_FLAGS" .. || exit 1
+
 make || exit 1
-echo "Build completed successfully"
+
+echo "Build completed successfully."

osx_environment.sh

@@ -11,7 +11,7 @@ function check_dir_exists() {
     fi
 }
 
-if [ ! $BARRIER_BUILD_ENV ]; then
+if [ ! "$BARRIER_BUILD_ENV" ]; then
     check_dir_exists '/Applications/Xcode.app' 'Xcode'
 
     printf "Modifying environment for Barrier build...\n"