Simplified regression handling

src/interfaces/ecpg/ecpglib/connect.c

src/interfaces/ecpg/ecpglib/data.c

src/interfaces/ecpg/ecpglib/extern.h

src/interfaces/ecpg/ecpglib/misc.c

src/interfaces/ecpg/preproc/ecpg.c

...interfaces/ecpg/test/expected/compat_informix-charfuncs.c

src/interfaces/ecpg/test/expected/compat_informix-dec_test.c

src/interfaces/ecpg/test/expected/compat_informix-rfmtdate.c

src/interfaces/ecpg/test/expected/compat_informix-rfmtlong.c

src/interfaces/ecpg/test/expected/compat_informix-rnull.c

...rfaces/ecpg/test/expected/compat_informix-test_informix.c

...faces/ecpg/test/expected/compat_informix-test_informix2.c

src/interfaces/ecpg/test/expected/connect-test1.c

src/interfaces/ecpg/test/expected/connect-test2.c

src/interfaces/ecpg/test/expected/connect-test3.c

src/interfaces/ecpg/test/expected/connect-test4.c

src/interfaces/ecpg/test/expected/connect-test5.c

src/interfaces/ecpg/test/expected/pgtypeslib-dt_test.c

src/interfaces/ecpg/test/expected/pgtypeslib-dt_test2.c

src/interfaces/ecpg/test/expected/pgtypeslib-num_test.c