portmap_6.0: Fix building on mipsel with gcc4.3

portmap_6.0: Fix building on mipsel with gcc4.3

with gcc-4.4 and provides the following:

| tmp/cross/mipsel/lib/gcc/mipsel-angstrom-linux/4.4.1/../../../../mipsel-angstrom-linux/bin/ld: portmap.o: relocation R_MIPS_HI16 against `__gnu_local_gp' can not be used when making a shared object; recompile with -fPIC

The CFLAGS in portmap's Makefile contains -fpie, but is ignored. The
CFLAGS I've added below are constructed from portmap's Makefile. When
built with gcc-4.3.3 the resultant binary no longer segfaults.

Signed-Off-By: Holger Hans Peter Freyther <zecke@selfish.org>