These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.98 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/xerces-c-3.3.0-r1:0/3.3::gentoo  USE="iconv icu -curl -doc -examples -static-libs -test" CPU_FLAGS_X86="sse2" 4211 KiB
[ebuild  N     ] dev-libs/xalan-c-1.12-r4:0/1.12::gentoo  USE="-doc -verify-sig" 1105 KiB

Total: 2 packages (2 new), Size of downloads: 5315 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by dev-libs/xalan-c-1.12-r4::gentoo
# required by =dev-libs/xalan-c-1.12-r4 (argument)
>=dev-libs/xerces-c-3.3.0-r1 icu