This patch removes redundant shell code and cleans it a little bit.

Shell macro compile_prog takes two arguments:
local_cflags and local ldflags.

$QEMU_CFLAGS is added automatically to the cflags, so there is no need
to pass it as an argument.

It is also unnecessary to pass -Werror twice.

$flag is a compiler warning option, so it should be in local_cflags
instead of local_ldflags.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>