Revert "no GDBM on Alpine at all"

This reverts commit f5d411a.

Author: mvorisek

.github/actions/configure-x64/action.yml

@@ -68,7 +68,7 @@ runs:
           --enable-inifile \
           --with-tcadb \
           --with-lmdb \
-          $(if [ -f /etc/alpine-release ]; then echo `#--with-gdbm`; else echo --with-qdbm; fi) \
+          $(if [ -f /etc/alpine-release ]; then echo --with-gdbm; else echo --with-qdbm; fi) \
           --with-snmp \
           --with-unixODBC \
           --with-imap \