depends: always configure with --with-pic

We currently do this sporadically. Not only amongst packages, but across
OS's, i.e sometimes it's done for BSDs/Android, and sometimes not.

Configure with `--with-pic` globally instead. I think this generally
makes more sense, and should not have any downsides.

See related discussion in
https://github.com/bitcoin/bitcoin/pull/28846#discussion_r1399123100.

depends/packages/expat.mk

@@ -11,7 +11,6 @@ define $(package)_set_vars
   $(package)_config_opts=--disable-shared --without-docbook --without-tests --without-examples
   $(package)_config_opts += --disable-dependency-tracking --enable-option-checking
   $(package)_config_opts += --without-xmlwf
-  $(package)_config_opts_linux=--with-pic
   $(package)_cppflags += -D_DEFAULT_SOURCE
 endef