Warning due to "utility" file in library being added as an include directory

[GoogleCodeExporter]

What steps will reproduce the problem?
1. In a sketchbook library (doesn't matter what, could just make a sample with 
sample.h empty inside of it), create a file named "utility".  (For instance, a 
partial implementation of the standard c++ library is how I found this out, but 
it doesn't have to actually contain anything.)
2. Add an include to a minimal project ensuring your library is added to the 
include path. (#include <sample.h>)
3. Try building.

What is the expected output? What do you see instead?
It succeeds, but warns excessively:
cc1plus.exe: warning: 
C:\Users\rpavlik\Desktop\src\nexus-omni4wd-arduino\libraries\StandardCplusplus\u
tility: not a directory [enabled by default]

The compile line goes something like:
C:\Program Files (x86)\arduino\hardware\tools\avr\bin\avr-g++ -c -g -Os -Wall 
-fno-exceptions -ffunction-sections -fdata-sections -mmcu=atmega328p 
-DF_CPU=16000000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=101 -IC:\Program 
Files (x86)\arduino\hardware\arduino\cores\arduino -IC:\Program Files 
(x86)\arduino\hardware\arduino\variants\standard 
-IC:\Users\rpavlik\Desktop\src\nexus-omni4wd-arduino\libraries\StandardCplusplus

-IC:\Users\rpavlik\Desktop\src\nexus-omni4wd-arduino\libraries\StandardCplusplus
\utility 
C:\Users\rpavlik\Desktop\src\nexus-omni4wd-arduino\libraries\StandardCplusplus\v
alarray.cpp -o 
C:\Users\rpavlik\AppData\Local\Temp\build2853684677234630722.tmp\StandardCpluspl
us\valarray.cpp.o 

So you can see that the _file_ libraries\StandardCplusplus\utility, because it 
exists, was added to the include path. Instead of just existence, the IDE 
should check for existence of a directory.

What version of the Arduino software are you using? On what operating
system?  Which Arduino board are you using?

1.0.1 on Windows 7, building for Uno in this example.

Original issue reported on code.google.com by ryan.pav...@gmail.com on 30 Aug 2012 at 8:14