Merge branch 'cb/reftable-fixup' into seen

Fixes to another topic.

* cb/reftable-fixup:
  openbsd: allow reftable building with zlib 1.2.3
  reftable: clarify zlib version dependency
  fixup! Provide zlib's uncompress2 from compat/zlib-compat.c

Author: gitster

Makefile

@@ -1751,7 +1751,7 @@ endif
 
 ifdef NO_UNCOMPRESS2
 	BASIC_CFLAGS += -DNO_UNCOMPRESS2
-	LIB_OBJS += compat/zlib-uncompress2.o
+	REFTABLE_OBJS += compat/zlib-uncompress2.o
 endif
 
 ifdef NO_POSIX_GOODIES

config.mak.uname

@@ -258,6 +258,7 @@ ifeq ($(uname_S),FreeBSD)
 	FILENO_IS_A_MACRO = UnfortunatelyYes
 endif
 ifeq ($(uname_S),OpenBSD)
+	NO_UNCOMPRESS2 = YesPlease
 	NO_STRCASESTR = YesPlease
 	NO_MEMMEM = YesPlease
 	USE_ST_TIMESPEC = YesPlease

reftable/block.c

@@ -16,7 +16,9 @@ license that can be found in the LICENSE file or at
 #include <zlib.h>
 
 #ifdef NO_UNCOMPRESS2
-/* This is uncompress2, which is only available in zlib as of 2017.
+/*
+ * This is uncompress2, which is only available in zlib >= 1.2.9
+ * (released as of early 2017)
  */
 int uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source,
 		uLong *sourceLen);