When building fvwm2-2.3.15-2 without autoconf present, ./configure is
automatically rerun (from the original run of ./configure). This subsequent
run does not honor the RPM_OPT_FLAGS (from CFLAGS), because the CFLAGS are
only set (CFLAGS="..." ./configure) and not exported from the shell
(CFLAGS="..."; export CFLAGS; ./configure). Therefore, the default "-O2 -g"
is activated and not the RPM_OPT_FLAGS.
was fixed in Beta3.