diff --git a/configure.ac b/configure.ac
index 328c332b5..353650e5f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -506,7 +506,6 @@ case "$DIFF_FLAGS" in
    fi
   ;;
 esac
-AC_SUBST(DIFF_FLAGS)
 
 # Stop tests for C++ and Fortran
 AC_DEFUN([AC_PROG_F77], [])
@@ -1777,6 +1776,9 @@ dnl		AC_MSG_ERROR([sqlcli1.h, sqlca.h, and sqludf.h are required for ODBC (DB2)]
   fi ],
 [])
 
+AC_ARG_VAR([OCI_CFLAGS], [compiler flags necessary to preprocess/compile for Oracle OCI])
+AC_ARG_VAR([OCI_LIBS], [linker flags for Oracle OCI, overriding automatic lookup])
+
 AC_ARG_WITH([oci],
 [AS_HELP_STRING([--with-oci],
   [Optionally use Oracle OCI for INDEXED/RELATIVE I/O])],
@@ -1936,6 +1938,9 @@ if test "$with_db" = "yes" -o "$with_db" = "check"; then
 	LIBS="$curr_libs"
 fi
 
+AC_ARG_VAR([LMDB_CFLAGS], [compiler flags necessary to preprocess/compile for LMDB])
+AC_ARG_VAR([LMDB_LIBS], [linker flags for LMDB, overriding automatic lookup])
+
 AC_ARG_WITH([lmdb],
 [AS_HELP_STRING([--with-lmdb],
   [Use Lightning Memory-Mapped Database (LMDB) for INDEXED I/O (experimental, no locking or shared storage, write is extremely slow)])],
@@ -2703,28 +2708,7 @@ AC_SUBST([COB_LIBRARY_PATH])
 AC_SUBST([COB_OBJECT_EXT])
 AC_SUBST([COB_MODULE_EXT])
 AC_SUBST([COB_EXE_EXT])
-AC_SUBST([QUOTE_INCLUDE_FLAG])
-AC_SUBST([COBC_CPPFLAGS])
-AC_SUBST([PROGRAMS_LIBS])
-AC_SUBST([LIBCOB_LIBS])
-AC_SUBST([LIBCOB_CPPFLAGS])
 AC_SUBST([LIBCOB_VER])
-AC_SUBST([CISAM_LIBS])
-AC_SUBST([DISAM_LIBS])
-AC_SUBST([VBISAM_LIBS])
-AC_SUBST([VISAM_LIBS])
-AC_SUBST([ODBC_LIBS])
-AC_SUBST([OCI_LIBS])
-AC_SUBST([BDB_LIBS])
-AC_SUBST([LMDB_LIBS])
-AC_SUBST([CISAM_CFLAGS])
-AC_SUBST([DISAM_CFLAGS])
-AC_SUBST([VBISAM_CFLAGS])
-AC_SUBST([VISAM_CFLAGS])
-AC_SUBST([ODBC_CFLAGS])
-AC_SUBST([OCI_CFLAGS])
-AC_SUBST([BDB_CFLAGS])
-AC_SUBST([LMDB_CFLAGS])
 
 dnl was used in bin/Makefile.am - seems not to be needed
 dnl AC_SUBST([COB_EXPORT_DYN])