Start working on removing those .la files en masse.

chromeos/config/make.conf.amd64-host

 # See "man make.conf" for the available options.
 
 ACCEPT_KEYWORDS="amd64"
 CHOST="x86_64-pc-linux-gnu"
 CFLAGS="-O2 -pipe"
 FEATURES="buildpkg -strict"
 
 # Since our portage comes from version control, we redirect distfiles
 DISTDIR="/var/lib/portage/distfiles"
 
@@ skipping 10 matching lines @@
 PKGDIR="/var/lib/portage/pkgs"
 
 FULL_BINHOST="http://commondatastorage.googleapis.com/chromeos-prebuilt/host/amd64/full-28.04.11.040331/packages/"
 PORTAGE_BINHOST="$FULL_BINHOST"
 
 USE="${USE} -cups hardened cros_host multilib pic pie"
 
 GENTOO_MIRRORS="http://commondatastorage.googleapis.com/chromeos-mirror/gentoo"
 GENTOO_MIRRORS="$GENTOO_MIRRORS http://commondatastorage.googleapis.com/chromeos-localmirror"
 
+
+# avoid removing libltdl.la as it is required by some macro files
+INSTALL_MASK="
+/usr/lib/lib[0-9]*.la
+/usr/lib/lib[a-k]*.la
+/usr/lib/lib[m-z]*.la
+/usr/lib/libl[0-9]*.la
+/usr/lib/libl[a-s]*.la
+/usr/lib/libl[u-z]*.la
+/usr/lib/liblt[0-9]*.la
+/usr/lib/liblt[a-c]*.la
+/usr/lib/liblt[e-z]*.la
+/usr/lib/libltd[0-9]*.la
+/usr/lib/libltd[a-k]*.la
+/usr/lib/libltd[m-z]*.la
+/usr/lib/libltdl[0-9]*.la
+/usr/lib/libltdl[a-z]*.la
+"
+
 source make.conf.host_setup