Yacc is another forgotten dependency.

cahirwpz · cahirwpz · commit 0bab2e953a68 · 2015-10-02T06:46:32.000+02:00
diff --git a/README.md b/README.md
@@ -73,6 +73,7 @@ You have to have following packages installed in your system:
  * git
  * subversion
  * patch
+ * yacc
 
 *For MacOSX users*: you'll likely need to have [MacPorts](http://www.macports.org) or [Homebrew](http://brew.sh) installed in order to build the toolchain.
 
diff --git a/toolchain-m68k b/toolchain-m68k
@@ -201,6 +201,7 @@ def build():
   find_executable('patch')
   find_executable('make')
   find_executable('git')
+  find_executable('yacc')
 
   with cwd('{archives}'):
     for url in URLS:
