thodg/libgit2

diff --git a/include/git2/sys/hashsig.h b/include/git2/sys/hashsig.h
new file mode 100644
index 0000000..cd735e1
--- /dev/null
+++ b/include/git2/sys/hashsig.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_hashsig_h__
+#define INCLUDE_sys_hashsig_h__
+
+#include "git2/common.h"
+
+GIT_BEGIN_DECL
+
+/**
+ * Similarity signature of line hashes for a buffer
+ */
+typedef struct git_hashsig git_hashsig;
+
+typedef enum {
+	GIT_HASHSIG_NORMAL = 0, /* use all data */
+	GIT_HASHSIG_IGNORE_WHITESPACE = 1, /* ignore whitespace */
+	GIT_HASHSIG_SMART_WHITESPACE = 2, /* ignore \r and all space after \n */
+} git_hashsig_option_t;
+
+/**
+ * Build a similarity signature for a buffer
+ *
+ * If you have passed a whitespace-ignoring buffer, then the whitespace
+ * will be removed from the buffer while it is being processed, modifying
+ * the buffer in place.  Sorry about that!
+ *
+ * This will return an error if the buffer doesn't contain enough data to
+ * compute a valid signature.
+ *
+ * @param out The array of hashed runs representing the file content
+ * @param buf The contents of the file to hash
+ * @param buflen The length of the data at `buf`
+ * @param generate_pairwise_hashes Should pairwise runs be hashed
+ */
+GIT_EXTERN(int) git_hashsig_create(
+	git_hashsig **out,
+	const char *buf,
+	size_t buflen,
+	git_hashsig_option_t opts);
+
+/**
+ * Build a similarity signature from a file
+ *
+ * This walks through the file, only loading a maximum of 4K of file data at
+ * a time.  Otherwise, it acts just like `git_hashsig_create`.
+ *
+ * This will return an error if the file doesn't contain enough data to
+ * compute a valid signature.
+ */
+GIT_EXTERN(int) git_hashsig_create_fromfile(
+	git_hashsig **out,
+	const char *path,
+	git_hashsig_option_t opts);
+
+/**
+ * Release memory for a content similarity signature
+ */
+GIT_EXTERN(void) git_hashsig_free(git_hashsig *sig);
+
+/**
+ * Measure similarity between two files
+ *
+ * @return <0 for error, [0 to 100] as similarity score
+ */
+GIT_EXTERN(int) git_hashsig_compare(
+	const git_hashsig *a,
+	const git_hashsig *b);
+
+GIT_END_DECL
+
+#endif
diff --git a/src/diff_tform.c b/src/diff_tform.c
index 423a0ca..9ebce06 100644
--- a/src/diff_tform.c
+++ b/src/diff_tform.c
@@ -8,9 +8,9 @@
 
 #include "git2/config.h"
 #include "git2/blob.h"
+#include "git2/sys/hashsig.h"
 
 #include "diff.h"
-#include "hashsig.h"
 #include "path.h"
 #include "fileops.h"
 #include "config.h"
diff --git a/src/hashsig.c b/src/hashsig.c
index 109f966..a6d5f20 100644
--- a/src/hashsig.c
+++ b/src/hashsig.c
@@ -4,7 +4,7 @@
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
  */
-#include "hashsig.h"
+#include "git2/sys/hashsig.h"
 #include "fileops.h"
 #include "util.h"
 
diff --git a/src/hashsig.h b/src/hashsig.h
deleted file mode 100644
index 8c920cb..0000000
--- a/src/hashsig.h
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright (C) the libgit2 contributors. All rights reserved.
- *
- * This file is part of libgit2, distributed under the GNU GPL v2 with
- * a Linking Exception. For full terms see the included COPYING file.
- */
-#ifndef INCLUDE_hashsig_h__
-#define INCLUDE_hashsig_h__
-
-#include "common.h"
-
-/**
- * Similarity signature of line hashes for a buffer
- */
-typedef struct git_hashsig git_hashsig;
-
-typedef enum {
-	GIT_HASHSIG_NORMAL = 0, /* use all data */
-	GIT_HASHSIG_IGNORE_WHITESPACE = 1, /* ignore whitespace */
-	GIT_HASHSIG_SMART_WHITESPACE = 2, /* ignore \r and all space after \n */
-} git_hashsig_option_t;
-
-/**
- * Build a similarity signature for a buffer
- *
- * If you have passed a whitespace-ignoring buffer, then the whitespace
- * will be removed from the buffer while it is being processed, modifying
- * the buffer in place.  Sorry about that!
- *
- * This will return an error if the buffer doesn't contain enough data to
- * compute a valid signature.
- *
- * @param out The array of hashed runs representing the file content
- * @param buf The contents of the file to hash
- * @param buflen The length of the data at `buf`
- * @param generate_pairwise_hashes Should pairwise runs be hashed
- */
-extern int git_hashsig_create(
-	git_hashsig **out,
-	const char *buf,
-	size_t buflen,
-	git_hashsig_option_t opts);
-
-/**
- * Build a similarity signature from a file
- *
- * This walks through the file, only loading a maximum of 4K of file data at
- * a time.  Otherwise, it acts just like `git_hashsig_create`.
- *
- * This will return an error if the file doesn't contain enough data to
- * compute a valid signature.
- */
-extern int git_hashsig_create_fromfile(
-	git_hashsig **out,
-	const char *path,
-	git_hashsig_option_t opts);
-
-/**
- * Release memory for a content similarity signature
- */
-extern void git_hashsig_free(git_hashsig *sig);
-
-/**
- * Measure similarity between two files
- *
- * @return <0 for error, [0 to 100] as similarity score
- */
-extern int git_hashsig_compare(
-	const git_hashsig *a,
-	const git_hashsig *b);
-
-#endif
diff --git a/src/merge.c b/src/merge.c
index ddeea87..1e72520 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -22,7 +22,6 @@
 #include "tree.h"
 #include "merge_file.h"
 #include "blob.h"
-#include "hashsig.h"
 #include "oid.h"
 #include "index.h"
 #include "filebuf.h"
@@ -42,6 +41,7 @@
 #include "git2/tree.h"
 #include "git2/oidarray.h"
 #include "git2/sys/index.h"
+#include "git2/sys/hashsig.h"
 
 #define GIT_MERGE_INDEX_ENTRY_EXISTS(X)	((X).mode != 0)
 #define GIT_MERGE_INDEX_ENTRY_ISFILE(X) S_ISREG((X).mode)
diff --git a/tests/core/buffer.c b/tests/core/buffer.c
index 7482dad..641fed6 100644
--- a/tests/core/buffer.c
+++ b/tests/core/buffer.c
@@ -1,7 +1,7 @@
 #include "clar_libgit2.h"
 #include "buffer.h"
 #include "buf_text.h"
-#include "hashsig.h"
+#include "git2/sys/hashsig.h"
 #include "fileops.h"
 
 #define TESTSTR "Have you seen that? Have you seeeen that??"
diff --git a/tests/merge/trees/treediff.c b/tests/merge/trees/treediff.c
index 2298a30..8b47f7d 100644
--- a/tests/merge/trees/treediff.c
+++ b/tests/merge/trees/treediff.c
@@ -3,7 +3,7 @@
 #include "merge.h"
 #include "../merge_helpers.h"
 #include "diff.h"
-#include "hashsig.h"
+#include "git2/sys/hashsig.h"
 
 static git_repository *repo;