Re: [PATCH v2 2/2] sha1dc: optionally use sha1collisiondetection as a submodule

Junio C Hamano [off-list ref] writes:

But when somebody (like me?) feels strongly enough, such a change
can always come on top of this patch, so let's have this
manual-configuration-only version as our first step.

Just so that I have something I can come back to, here it is with a
log message.

-- >8 --
Subject: [PATCH] sha1collisiondetection: automatically enable when submodule is populated

If a user wants to experiment with the version of collision
detecting sha1 from the submodule, the user needed to not just
populate the submodule but also needed to turn the knob.

A Makefile trick is easy enough to do so, so let's do this.  When
somebody with a copy of the submodule populated wants not to use it,
that can be done by overriding it in config.mak or from the command
line, e.g. "make DC_SHA1_SUBMODULE= all".

Signed-off-by: Junio C Hamano <redacted>
---
 Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile b/Makefile
index 6baad1669e..8d33936a12 100644
--- a/Makefile
+++ b/Makefile

@@ -989,6 +989,10 @@ EXTLIBS =
 
 GIT_USER_AGENT = git/$(GIT_VERSION)
 
+ifeq ($(wildcard sha1collisiondetection/lib/sha1.h),sha1collisiondetection/lib/sha1.h)
+DC_SHA1_SUBMODULE = auto
+endif
+
 include config.mak.uname
 -include config.mak.autogen
 -include config.mak

-- 
2.13.0-440-g3ce6d2d5b8