diff --git a/Makefile b/Makefile
index 5403fad3e8..f666d2f1b7 100644
--- a/Makefile
+++ b/Makefile
@@ -911,6 +911,7 @@ ifdef MSVC
 	NO_REGEX = YesPlease
 	NO_CURL = YesPlease
 	NO_PTHREADS = YesPlease
+	BLK_SHA1 = YesPlease
 
 	CC = compat/vcbuild/scripts/clink.pl
 	AR = compat/vcbuild/scripts/lib.pl
@@ -960,6 +961,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	UNRELIABLE_FSTAT = UnfortunatelyYes
 	OBJECT_CREATION_USES_RENAMES = UnfortunatelyNeedsTo
 	NO_REGEX = YesPlease
+	BLK_SHA1 = YesPlease
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/fnmatch
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
 	COMPAT_OBJS += compat/mingw.o compat/fnmatch/fnmatch.o compat/winansi.o