odb: split `struct odb_source` into separate header

Subsequent commits will expand the `struct odb_source` to become a
generic interface for accessing an object database source. As part of
these refactorings we'll add a set of function pointers that will
significantly expand the structure overall.

Prepare for this by splitting out the `struct odb_source` into a
separate header. This keeps the high-level object database interface
detached from the low-level object database sources.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 47ed9fa7fd..116358e484 100644
--- a/Makefile
+++ b/Makefile
@@ -1214,6 +1214,7 @@ LIB_OBJS += object-file.o
 LIB_OBJS += object-name.o
 LIB_OBJS += object.o
 LIB_OBJS += odb.o
+LIB_OBJS += odb/source.o
 LIB_OBJS += odb/streaming.o
 LIB_OBJS += oid-array.o
 LIB_OBJS += oidmap.o