source build non 4.8 Bdb headers issue #3943

4.8 Bdb headers were not found however 4.8 so is found and hence the build still uses 4.8 so and hence making it incompatible with 5.1 db wallet.

found below in ./configure output.

configure: WARNING: Found Berkeley DB other than 4.8; wallets opened by this build will not be portable! checking for main in -ldb_cxx-4.8... yes

I suppose the header files and so files should be of same version and in case its made for incompatible bdb then not to check for cxx.

took me 2 day to figure out the issue.

@luke-jr bitcoin_find_bdb48.m4 is your baby. Would you like to look into this? Otherwise I'm happy to track it down.

Based on a cursory glance looks like line 55-66 of bitcoin_find_bdb48.m4 might be the cause of the issue.

56: for searchlib in db_cxx-4.8 db_cxx;

if db_cxx found it stops there but there should be a validation on what option is selected.

Duplicate of #3921. Would still be nice to have explicit options to set the path to BDB, especially as the recommended version 4.8 is nowhere available as system version anymore.