libgtest.a needs to be built with -fPIC

Currently, only the shared library version of libgtest is compiled with -fPIC, but the shared library is not distributed. This creates a problem when linking with other code compiled with -fPIC:

cndougla@cndougla:~/Canonical/ubuntu/xorg-server/xorg-server/build-main/test/integration$ /bin/bash ../../libtool --tag=CXX --mode=link g++ -DDUMMY_CONF_PATH=/usr/share/xorg/gtest/dummy.conf -g -O0 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security -Werror=format-security -lpthread -Wl,-Bsymbolic-functions -pie -Wl,-z,relro -Wl,-Bsymbolic -o integration-test two_window_test.o two_window_touch_test.o one_accept.o -lgtest -lxorg-gtest_main -lxorg-gtest -lXi -lutouch-evemu -lm -lrt
libtool: link: g++ -DDUMMY_CONF_PATH=/usr/share/xorg/gtest/dummy.conf -g -O0 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security -Werror=format-security -Wl,-Bsymbolic-functions -pie -Wl,-z -Wl,relro -Wl,-Bsymbolic -o integration-test two_window_test.o two_window_touch_test.o one_accept.o -lpthread -lgtest -lxorg-gtest_main -lxorg-gtest -lXi -lutouch-evemu -lm -lrt
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libgtest.a(gtest-all.cc.o): relocation R_X86_64_32S against `vtable for testing::internal::TestEventRepeater' can not be used when making a shared object; recompile with -fPIC
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libgtest.a: could not read symbols: Bad value
collect2: ld returned 1 exit status