configure: do not enable AltiVec in libvlccore

This was added ostensibly to fix compilation of the run-time AltiVec
test which was removed in bc146294.
Unfortunately, it causes the compiler to emit AltiVec instructions,
such that the executable crashes if AltiVec is not available.

Regression from e48d6195.

configure.ac

@@ -1683,7 +1683,6 @@ AS_IF([test "${enable_altivec}" = "yes"], [
   AS_IF([test "${ac_cv_altivec_inline}" != "no"], [
     AS_IF([test "${ac_cv_altivec_inline}" != "yes"], [
       ALTIVEC_CFLAGS="${ac_cv_altivec_inline}"
-      VLC_ADD_CFLAGS([libvlccore],[${ac_cv_altivec_inline}])
     ])
     have_altivec="yes"
   ])
@@ -1704,7 +1703,6 @@ AS_IF([test "${enable_altivec}" = "yes"], [
   AS_IF([test "${ac_cv_c_altivec}" != "no"], [
     CPPFLAGS="${CPPFLAGS} ${ac_cv_c_altivec}"
     AC_DEFINE(CAN_COMPILE_C_ALTIVEC, 1, [Define to 1 if C AltiVec extensions are available.])
-    VLC_ADD_CFLAGS([libvlccore],[${ac_cv_c_altivec}])
     ALTIVEC_CFLAGS="$ALTIVEC_CFLAGS ${ac_cv_c_altivec}"
     VLC_ADD_CFLAGS([deinterlace],[${ac_cv_c_altivec}])
     have_altivec="yes"