depends: Fix issue cross-compiling BDB to Windows with Clang 12

depends/packages/bdb.mk

@@ -4,7 +4,7 @@ $(package)_download_path=https://download.oracle.com/berkeley-db
 $(package)_file_name=db-$($(package)_version).tar.gz
 $(package)_sha256_hash=47612c8991aa9ac2f6be721267c8d3cdccf5ac83105df8e50809daea24e95dc7
 $(package)_build_subdir=build_unix
-$(package)_patches=winioctl-and-atomic_init_db.patch
+$(package)_patches=clang-12-stpcpy-issue.diff winioctl-and-atomic_init_db.patch
 
 ifneq ($(host_os),darwin)
 $(package)_dependencies=libcxx
@@ -30,6 +30,7 @@ endif
 endef
 
 define $(package)_preprocess_cmds
+  patch -p1 <$($(package)_patch_dir)/clang-12-stpcpy-issue.diff && \
   patch -p1 <$($(package)_patch_dir)/winioctl-and-atomic_init_db.patch
 endef
 

depends/patches/bdb/clang-12-stpcpy-issue.diff

@@ -0,0 +1,25 @@
+diff -ur db-6.2.23-orig/src/blob/blob_util.c db-6.2.23/src/blob/blob_util.c
+--- db-6.2.23-orig/src/blob/blob_util.c	2016-03-28 20:45:53.000000000 +0100
++++ db-6.2.23/src/blob/blob_util.c	2021-07-30 18:07:29.942811600 +0100
+@@ -544,7 +544,20 @@
+ 		goto err;
+
+ 	memset(path, 0, len);
+-	name_len += sprintf(path, "%s", blob_sub_dir);
++	// name_len += sprintf(path, "%s", blob_sub_dir);
++	{
++		// Clang 12 introduced an "libcall optimization" that lowers the above
++		// to stpcpy to avoid the machinery involved in parsing format strings.
++		// This causes build problems when cross-compiling to Windows with the
++		// version of mingw-w64 that Zcash supports. We haven't figured out why
++		// but in the meantime we replace this with an inlined stpcpy impl from
++		// https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=5934637641c863cc2c1765a0d01c5b6f53ecc4fc
++		char *dest = path;
++		const char *src = blob_sub_dir;
++		while ((*dest++ = *src++) != '\0')
++			/* nothing */;
++		name_len += (--dest - path);
++	}
+
+ 	__blob_calculate_dirs(blob_id, path, &name_len, &depth);
+