Merge pull request #10 from mayah/master

Reduce link warning and make CXX_LDFLAGS more flexible to add user options.
GCCFLAGS can be added by the user.
Fixed a wrong size argument of memset.
Stub implementation of statfs64 and fstatfs64.
Add a testcase for strlcpy
Improve strlcpy performance on most case.

glibc strncpy is unbelievably slow if size is much larger than
strlen(src); e.g. 16K bytes vs 64 bytes.

Bug fix:
The length of src should be returned.
https://developer.apple.com/library/mac/#documentation/darwin/reference/manpages/man3/strlcpy.3.html
Add a few more comments on strlcpy
Update unpack_xcode.sh

Now it works for Xcode 4.3.3, 4.4.1, 4.5.2, 4.6.2, and 5.0.1.
It seems clang and ld in Xcode 4.X works, but binaries in 5.0.1
just crashes.
Update the document a bit
Handle LC_MAIN to support tools in Xcode 5

include/mach-o/loader.h is updated.
Use clang automatically when USE_LIBCXX is specified
Update README to explain how to run recent Xcode tools
Dummy implementation of __cxa_demangle.

Minir fix:
- fixed spelling mistake.