t/t3030-merge-recursive.sh: use the $( ... ) construct for command substitution

diff --git a/sha1_file.c b/sha1_file.c
index 2c68766ebf0cab5f13f684ac3e26061b93bda44a..73ccd49a465b1cf8b668edf8c13ea75d6b8de718 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -36,6 +36,7 @@
 static inline uintmax_t sz_fmt(size_t s) { return s; }
 
 const unsigned char null_sha1[20];
+const struct object_id null_oid;
 
 /*
  * This is meant to hold a *small* number of objects that you would