seeks: fix compile on platforms with VFP

reported by buildbot on sunxi

configure fails to detect C++ compiler:
a.out uses VFP register arguments, /tmp/ccHPrqts.o does not

other errors when linking:
ld: error: .libs/libseeksutils.so.0.0.0 uses VFP register arguments, .libs/miscutil.o does not
ld: error: .libs/libseeksutils.so.0.0.0 uses VFP register arguments, .libs/mem_utils.o does not
ld: error: .libs/libseeksutils.so.0.0.0 uses VFP register arguments, .libs/mutexes.o does not

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>