gitattributes: add attributes file

On different platforms, line endings can differ. Git tries to
intelligently convert source code to match native line endings when
doing a checkout, unless a particular configuration flag is set.

An alternate approach is to create a `.gitattributes` file and manually
specify various types of files. This ensures files are properly handled.
It also prevents git from creating patches that consist of nothing more
than replacing line endings.

Signed-off-by: Sean Cross <sean@xobs.io>

.gitattributes

@@ -0,0 +1,40 @@
+# Text for humans
+LICENSE text eol=lf
+HACKING text eol=lf
+COPYING text eol=lf
+UsingSWO text eol=lf
+README.* text eol=lf
+
+# Source code
+Makefile text eol=lf
+*.mk text eol=lf
+*.mak text eol=lf
+*.inc text eol=lf
+*.py text eol=lf
+*.sh text eol=lf
+*.c text eol=lf
+*.S text eol=lf
+*.s text eol=lf
+*.h text eol=lf
+*.ld text eol=lf
+*.yml text eol=lf
+*.rules text eol=lf
+
+# Git control files
+.gitattributes eol=lf
+.gitignore eol=lf
+.gitmodules eol=lf
+
+# Windows source code uses CRLF
+*.vcxproj text eol=crlf
+*.props text eol=crlf
+*.bat text eol=crlf
+*.ps1 text eol=crlf
+*.inf text eol=crlf
+
+# Other binary files
+*.png binary
+*.jpg binary
+*.bin binary
+*.elf binary
+*.bin binary