ENH: fix for darwin from eric wing

Modules/FindDoxygen.cmake

@@ -2,18 +2,42 @@
 # this module looks for Doxygen and the path to Graphiz's dot
 #
 
+# With the OS X GUI version, it likes to be installed to /Applications and
+# it contains the doxygen executable in the bundle. In the versions I've 
+# seen, it is located in Resources, but in general, more often binaries are 
+# located in MacOS.
 FIND_PROGRAM(DOXYGEN
   doxygen
   "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\doxygen_is1;Inno Setup: App Path]/bin"
+  /Applications/Doxygen.app/Contents/Resources
+  /Applications/Doxygen.app/Contents/MacOS
 )
 
+# In the older versions of OS X Doxygen, dot was included with the 
+# Doxygen bundle. But the new versions place make you download Graphviz.app
+# which contains dot in its bundle.
 FIND_PROGRAM(DOT
   dot
   "C:/Program Files/ATT/Graphviz/bin"
   [HKEY_LOCAL_MACHINE\\SOFTWARE\\ATT\\Graphviz;InstallPath]/bin
+  /Applications/Graphviz.app/Contents/MacOS
+  /Applications/Doxygen.app/Contents/Resources
+  /Applications/Doxygen.app/Contents/MacOS
+)
+
+# The Doxyfile wants the path to Dot, not the entire path and executable
+# so for convenience, I'll add another search for DOT_PATH.
+FIND_PATH(DOT_PATH
+  dot
+  "C:/Program Files/ATT/Graphviz/bin"
+  [HKEY_LOCAL_MACHINE\\SOFTWARE\\ATT\\Graphviz;InstallPath]/bin
+  /Applications/Graphviz.app/Contents/MacOS
+  /Applications/Doxygen.app/Contents/Resources
+  /Applications/Doxygen.app/Contents/MacOS
 )
 
 MARK_AS_ADVANCED(
   DOT
+  DOT_PATH
   DOXYGEN
 )