Makefile:
* append CFLAGS, do not set
* use CFLAGS when linking (for -m32 etc)
ioping.spec:
* pass RPM_OPT_FLAGS to make in environment

While at it, also:
* Makefile: move compiler/linker options before file names
* Makefile: move -lm to where it belongs (LDFLAGS)
Signed-off-by: Kir Kolyshkin <kir@openvz.org>