These can be static

src/remote.c

@@ -687,7 +687,7 @@ int set_transport_callbacks(git_transport *t, const git_remote_callbacks *cbs)
 				cbs->certificate_check, cbs->payload);
 }
 
-int set_transport_custom_headers(git_transport *t, const git_strarray *custom_headers)
+static int set_transport_custom_headers(git_transport *t, const git_strarray *custom_headers)
 {
 	if (!t->set_custom_headers || !custom_headers)
 		return 0;

src/transports/smart.c

@@ -66,7 +66,7 @@ static int git_smart__set_callbacks(
 	return 0;
 }
 
-int http_header_name_length(const char *http_header)
+static int http_header_name_length(const char *http_header)
 {
 	const char *colon = strchr(http_header, ':');
 	if (!colon)
@@ -74,7 +74,7 @@ int http_header_name_length(const char *http_header)
 	return colon - http_header;
 }
 
-bool is_malformed_http_header(const char *http_header)
+static bool is_malformed_http_header(const char *http_header)
 {
 	const char *c;
 	int name_len;
@@ -104,7 +104,7 @@ static char *forbidden_custom_headers[] = {
 	"Content-Length",
 };
 
-bool is_forbidden_custom_header(const char *custom_header)
+static bool is_forbidden_custom_header(const char *custom_header)
 {
 	unsigned long i;
 	int name_len = http_header_name_length(custom_header);