[PATCH/RFC 2/3] sha1dc: use sha1collisiondetection as a submodule

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Now that we don't need local modifications to the code anymore with my
avar/sha1collisiondetection:easier-inclusion-in-other-programs branch
we can use the upstream code-as is.

If and when this change gets accepted by upstream we should of course
point to the https://github.com/cr-marcstevens/sha1collisiondetection
master branch instead.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 .gitmodules            | 4 ++++
 Makefile               | 8 ++++----
 hash.h                 | 2 +-
 sha1collisiondetection | 1 +
 4 files changed, 10 insertions(+), 5 deletions(-)
 create mode 100644 .gitmodules
 create mode 160000 sha1collisiondetection

diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000..b60238a087
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,4 @@
+[submodule "sha1collisiondetection"]
+	path = sha1collisiondetection
+	url = https://github.com/avar/sha1collisiondetection.git
+	branch = easier-inclusion-in-other-programs
diff --git a/Makefile b/Makefile
index 342466d83a..63223fd02f 100644
--- a/Makefile
+++ b/Makefile
@@ -1412,15 +1412,15 @@ ifdef APPLE_COMMON_CRYPTO
 	BASIC_CFLAGS += -DSHA1_APPLE
 else
 	DC_SHA1 := YesPlease
-	LIB_OBJS += sha1dc/sha1.o
-	LIB_OBJS += sha1dc/ubc_check.o
+	LIB_OBJS += sha1dc/lib/sha1.o
+	LIB_OBJS += sha1dc/lib/ubc_check.o
 	BASIC_CFLAGS += \
 		-DSHA1_DC \
 		-DSHA1DC_NO_STANDARD_INCLUDES \
 		-DSHA1DC_INIT_SAFE_HASH_DEFAULT=0 \
 		-DSHA1DC_CUSTOM_INCLUDE_SHA1_C="\"cache.h\"" \
-		-DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C="\"../sha1dc_git.c\"" \
-		-DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H="\"../sha1dc_git.h\"" \
+		-DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C="\"../../sha1dc_git.c\"" \
+		-DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H="\"../../sha1dc_git.h\"" \
 		-DSHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C="\"git-compat-util.h\""
 endif
 endif
diff --git a/hash.h b/hash.h
index a11fc9233f..e585237136 100644
--- a/hash.h
+++ b/hash.h
@@ -8,7 +8,7 @@
 #elif defined(SHA1_OPENSSL)
 #include <openssl/sha.h>
 #elif defined(SHA1_DC)
-#include "sha1dc/sha1.h"
+#include "sha1dc/lib/sha1.h"
 #else /* SHA1_BLK */
 #include "block-sha1/sha1.h"
 #endif
diff --git a/sha1collisiondetection b/sha1collisiondetection
new file mode 160000
index 0000000000..5423dd8bcf
--- /dev/null
+++ b/sha1collisiondetection
@@ -0,0 +1 @@
+Subproject commit 5423dd8bcf3cdbd029dfa08d5d5f6dc044f7ac6d
-- 
2.13.0.303.g4ebf302169