Prism.languages.c = Prism.languages.extend('clike', {
  keyword: /\b(?:_Alignas|_Alignof|_Atomic|_Bool|_Complex|_Generic|_Imaginary|_Noreturn|_Static_assert|_Thread_local|asm|typeof|inline|auto|break|case|char|const|continue|default|do|double|else|enum|extern|float|for|goto|if|int|long|register|return|short|signed|sizeof|static|struct|switch|typedef|union|unsigned|void|volatile|while)\b/,
  operator: /-[>-]?|\+\+?|!=?|<<?=?|>>?=?|==?|&&?|\|\|?|[~^%?*\/]/,
  number: /(?:\b0x[\da-f]+|(?:\b\d+\.?\d*|\B\.\d+)(?:e[+-]?\d+)?)[ful]*/i,
});

Prism.languages.insertBefore('c', 'string', {
  macro: {
    // allow for multiline macro definitions
    // spaces after the # character compile fine with gcc
    pattern: /(^\s*)#\s*[a-z]+(?:[^\r\n\\]|\\(?:\r\n|[\s\S]))*/im,
    lookbehind: true,
    alias: 'property',
    inside: {
      // highlight the path of the include statement as a string
      string: {
        pattern: /(#\s*include\s*)(?:<.+?>|("|')(?:\\?.)+?\2)/,
        lookbehind: true,
      },
      // highlight macro directives as keywords
      directive: {
        pattern: /(#\s*)\b(?:define|defined|elif|else|endif|error|ifdef|ifndef|if|import|include|line|pragma|undef|using)\b/,
        lookbehind: true,
        alias: 'keyword',
      },
    },
  },
  // highlight predefined macros as constants
  constant: /\b(?:__FILE__|__LINE__|__DATE__|__TIME__|__TIMESTAMP__|__func__|EOF|NULL|SEEK_CUR|SEEK_END|SEEK_SET|stdin|stdout|stderr)\b/,
});

delete Prism.languages.c['class-name'];
delete Prism.languages.c['boolean'];
