title: error: unknown type name ‘bool’
body: <p>I downloaded the source code and wanted to compile the file of scanner.  It produces this error:</p>
  
  <pre><code>[meepo@localhost cs143-pp1]$ gcc -o lex.yy.o lex.yy.c -ll
  In file included from scanner.l:15:0:
  scanner.h:59:5: error: unknown type name ‘bool’
  In file included from scanner.l:16:0:
  utility.h:64:38: error: unknown type name ‘bool’
  utility.h:74:1: error: unknown type name ‘bool’
  In file included from scanner.l:17:0:
  errors.h:16:18: fatal error: string: No such file or directory
  compilation terminated.
  </code></pre>
  
  <p>And I tried to use different complier to compile it, but it appeared different errors.</p>
  
  <pre><code>[meepo@localhost cs143-pp1]$ g++ -o scan lex.yy.c -ll
  /usr/bin/ld: cannot find -ll
  collect2: ld returned 1 exit status
  </code></pre>
  
  <p>My os is 3.0-ARCH, I don't know why this happened. How do I fix the error?</p>