package/berkeleydb: add option for historic dbm interface

Berkeley DB support in python depends on dbm, when missing python fails
to detect libdb:
https://github.com/python/cpython/blob/d2340ef25721b6a72d45d4508c672c4be38c67d3/configure.ac#L4002

quoting python configure log:
checking for libdb... no

quoting python config.log:
conftest.c:(.text.startup+0x8): undefined reference to `__db_ndbm_open'

This patch provides a configure option for the historic dbm interface
to be used by the python package.

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/berkeleydb/Config.in

@@ -13,6 +13,11 @@ config BR2_PACKAGE_BERKELEYDB_COMPAT185
 	help
 	  Build and install DB 1.85 compatibility API.
 
+config BR2_PACKAGE_BERKELEYDB_DBM
+	bool "historic dbm interface"
+	help
+	  Enable the historic dbm interface.
+
 config BR2_PACKAGE_BERKELEYDB_TOOLS
 	bool "install tools"
 	help

package/berkeleydb/berkeleydb.mk

@@ -39,6 +39,7 @@ define BERKELEYDB_CONFIGURE_CMDS
 		--disable-java \
 		--disable-tcl \
 		$(if $(BR2_PACKAGE_BERKELEYDB_COMPAT185),--enable-compat185,--disable-compat185) \
+		$(if $(BR2_PACKAGE_BERKELEYDB_DBM),--enable-dbm,--disable-dbm) \
 		$(SHARED_STATIC_LIBS_OPTS) \
 		--with-pic \
 		--enable-o_direct \