app-text/texlive-core-2017-r4::gentoo was built with the following: USE="luajittex -X -cjk -doc -source -tk -xetex" ABI_X86="(64)" CXXFLAGS="-O2 -pipe -march=ivybridge -mtune=ivybridge -mno-xsaveopt -Wno-error=missing-prototypes -Wno-error=enum-compare -Wno-error=unused-function -Wno-error=deprecated-declarations -frecord-gcc-switches -std=c++11" After updating dev-libs/icu from v61.1 to v62.1 I got !!! existing preserved libs: >>> package: dev-libs/icu-62.1 * - /usr/lib64/libicudata.so.60 * - /usr/lib64/libicudata.so.60.2 * - /usr/lib64/libicui18n.so.60 * - /usr/lib64/libicui18n.so.60.2 * used by /usr/bin/upmendex (app-text/texlive-core-2017-r4) * - /usr/lib64/libicuuc.so.60 * - /usr/lib64/libicuuc.so.60.2 * used by /usr/bin/upmendex (app-text/texlive-core-2017-r4) So it looks like there's some automagic on icu... Please don't forget to add a sub slot operator.