Specify line endings in .gitattributes.

GN expects Unix line endings. This is necessary at least for some types
of tests and setting this helps keeps things consistent.

Change-Id: Ic9a60baa30c6140448bb741ea5b57e129a7a35c8
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/15140
Reviewed-by: Takuto Ikuta <tikuta@google.com>
Commit-Queue: Brett Wilson <brettw@chromium.org>

.gitattributes

diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..38d0989
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,17 @@
+# We expect files to have Unix line endings.
+*.c text eol=lf
+*.cc text eol=lf
+*.cpp text eol=lf
+*.gn text eol=lf
+*.gni text eol=lf
+*.h text eol=lf
+*.md text eol=lf
+*.py text eol=lf
+*.txt text eol=lf
+.clang-format text eol=lf
+.gitattributes text eol=lf
+.gitignore text eol=lf
+AUTHORS text eol=lf
+LICENSE text eol=lf
+OWNERS text eol=lf
+README.* text eol=lf