ngx-sharebuttons: Error with build

Bug Report or Feature Request (mark with an x)

- [x] bug report -> please search issues before submitting
- [ ] feature request
- [ ] question

OS and Version

Happening mainly on Circle CI’s circleci/node:boron-browsers image

Versions

Angular CLI: 1.6.4
Node: 8.9.4
OS: darwin x64
Angular: 5.2.0
... animations, common, compiler, compiler-cli, core, forms
... http, platform-browser, platform-browser-dynamic
... platform-server, router, service-worker

@angular/cli: 1.6.4
@angular/tsc-wrapped: 5.0.0-beta.7
@angular-devkit/build-optimizer: 0.0.38
@angular-devkit/core: 0.0.25
@angular-devkit/schematics: 0.0.48
@ngtools/json-schema: 1.1.0
@ngtools/webpack: 1.9.4
@schematics/angular: 0.1.13
@schematics/schematics: 0.0.13
typescript: 2.4.2
webpack: 3.10.0

Repro steps

Not sure. This is a production app with a lot of things going on. I ran into trouble when updating to the newest version and have been running into trouble just trying to downgrade. The problem mainly occurs during the build step. It seems like there’s some dependency errors as well as an additional syntax issue.

The log given by the failure

ERROR in ./node_modules/raw-loader!./node_modules/postcss-loader/lib??embedded!./node_modules/sass-loader/lib/loader.js??ref--8-3!./src/styles.scss
Module build failed: 
  --button-color: $sb-more !important;

                ^
      Invalid CSS after "...color: $sb-more": expected "}", was "!important;"
      in /home/circleci/web-2/node_modules/@ngx-share/button/styles/share-buttons.scss (line 103, column 18)
ERROR in ./node_modules/@ngx-share/button/esm5/ngx-share-button.js
Module not found: Error: Can't resolve '@fortawesome/angular-fontawesome' in '/home/circleci/web-2/node_modules/@ngx-share/button/esm5'