diff --git a/Makefile b/Makefile
index 1f6a50d3c3..e1a37d1efd 100644
--- a/Makefile
+++ b/Makefile
@@ -1776,7 +1776,9 @@ builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \
 version.sp version.s version.o: GIT-VERSION-FILE GIT-USER-AGENT
 version.sp version.s version.o: EXTRA_CPPFLAGS = \
 	'-DGIT_VERSION="$(GIT_VERSION)"' \
-	'-DGIT_USER_AGENT=$(GIT_USER_AGENT_CQ_SQ)'
+	'-DGIT_USER_AGENT=$(GIT_USER_AGENT_CQ_SQ)' \
+	'-DGIT_BUILT_FROM_COMMIT="$(shell git rev-parse -q --verify HEAD || \
+		echo "(unknown)")"'
 
 $(BUILT_INS): git$X
 	$(QUIET_BUILT_IN)$(RM) $@ && \
diff --git a/help.c b/help.c
index 7244276ded..21fbf408e5 100644
--- a/help.c
+++ b/help.c
@@ -433,6 +433,8 @@ int cmd_version(int argc, const char **argv, const char *prefix)
 	printf("git version %s\n", git_version_string);
 	while (*++argv) {
 		if (!strcmp(*argv, "--build-options")) {
+			printf("built from commit: %s\n",
+			       git_built_from_commit_string);
 			printf("sizeof-long: %d\n", (int)sizeof(long));
 			printf("machine: %s\n", build_platform);
 			/* NEEDSWORK: also save and output GIT-BUILD_OPTIONS? */
diff --git a/http.c b/http.c
index 05583c0e30..a763e10025 100644
--- a/http.c
+++ b/http.c
@@ -109,7 +109,7 @@ static int curl_save_cookies;
 struct credential http_auth = CREDENTIAL_INIT;
 static int http_proactive_auth;
 static const char *user_agent;
-static int curl_empty_auth;
+static int curl_empty_auth = 1;
 
 #if LIBCURL_VERSION_NUM >= 0x071700
 /* Use CURLOPT_KEYPASSWD as is */
diff --git a/version.c b/version.c
index 6106a8098c..41b718c29e 100644
--- a/version.c
+++ b/version.c
@@ -3,6 +3,7 @@
 #include "strbuf.h"
 
 const char git_version_string[] = GIT_VERSION;
+const char git_built_from_commit_string[] = GIT_BUILT_FROM_COMMIT;
 
 const char *git_user_agent(void)
 {
diff --git a/version.h b/version.h
index 6911a4f155..7c62e80577 100644
--- a/version.h
+++ b/version.h
@@ -2,6 +2,7 @@
 #define VERSION_H
 
 extern const char git_version_string[];
+extern const char git_built_from_commit_string[];
 
 const char *git_user_agent(void);
 const char *git_user_agent_sanitized(void);