Create a git ignore file for openmp runtime

[guansong]

Summary

Create a git ignore file for openmp runtime, based on the .gitignore file in llvm root dir

[jlpeyton]

Fix, then commit

.gitignore

25–26

Put this in the "Directories to ignore" section at the bottom

[guansong]

As suggested, mv the dir to the empty dir down below

.gitignore

+#==============================================================================#
+# This file specifies intentionally untracked files that git should ignore.
+# See: http://www.kernel.org/pub/software/scm/git/docs/gitignore.html
+#
+# This file is intentionally different from the output of `git svn show-ignore`,
+# as most of those are useless.
+#==============================================================================#
+
+#==============================================================================#
+# File extensions to be ignored anywhere in the tree.
+#==============================================================================#
+# Temp files created by most text editors.
+*~
+# Merge files created by git.
+*.orig
+# Byte compiled python modules.
+*.pyc
+# vim swap files
+.*.sw?
+.sw?
+#OS X specific files.
+.DS_store
+
+#==============================================================================#
+# Explicit files to ignore (only matches one).
+#==============================================================================#
+# Various tag programs
+tags
+/TAGS
+/GPATH
+/GRTAGS
+/GSYMS
+/GTAGS
+.gitusers
+
+#==============================================================================#
+# Directories to ignore (do not add trailing '/'s, they skip symlinks).
+#==============================================================================#
+runtime/exports
+
+# Nested build directory
+/build
+