[m-rev.] bdwgc diff: Add libatomoc_ops/ as a git submodule

[Paul Bone]

.gitmodules:
libatomic_ops:
    As above.

.gitignore:
    Remove libatomic_ops from .gitignore.
---
 .gitignore    | 1 -
 .gitmodules   | 6 ++++++
 libatomic_ops | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 .gitmodules
 create mode 160000 libatomic_ops

diff --git a/.gitignore b/.gitignore
index 51d1205..b4d0067 100644
--- a/.gitignore
+++ b/.gitignore
@@ -79,7 +79,6 @@ config.h.in~
 stamp-h1
 
 # External library (without trailing slash to allow symlinks):
-/libatomic_ops*
 /libatomic_ops-install
 /pthreads-w32*
 
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..e68b7e7
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "libatomic_ops"]
+	path = libatomic_ops
+	url = ../libatomic_ops.git
+	branch = release-7_4-mercury
+	ignore = dirty
+	update = checkout
diff --git a/libatomic_ops b/libatomic_ops
new file mode 160000
index 0000000..137001b
--- /dev/null
+++ b/libatomic_ops
@@ -0,0 +1 @@
+Subproject commit 137001b1d9bddc0034de887c8e6ebc32893b1821
-- 
2.6.1