stsp@ told me that FETCH_PACKAGES=Yes was not totally broken, I just have to manually do "# pkg_delete quirks" every time I want to build a port:
$ cd /usr/ports/www/mozilla-firefox && make ===> firefox-45.0.1 depends on: gcc-libs->=4.9,<4.10 -> gcc-libs-4.9.3p4 ===> firefox-45.0.1 depends on: nss->=3.21.1 -> nss-3.23 ===> firefox-45.0.1 depends on: nspr->=4.12 -> nspr-4.12p0 ===> firefox-45.0.1 depends on: hunspell-* -> hunspell-1.3.2p2 ===> firefox-45.0.1 depends on: icu4c-* -> icu4c-56.1p1 ===> firefox-45.0.1 depends on: xz-* -> xz-5.2.2p0 ===> firefox-45.0.1 depends on: gmake-* -> gmake-4.1p1 ===> firefox-45.0.1 depends on: llvm->=3.7.1 -> llvm-3.7.1p0 ===> firefox-45.0.1 depends on: python->=2.7,<2.8 -> python-2.7.11p0 ===> firefox-45.0.1 depends on: gettext-tools-* -> gettext-tools-0.19.7p0 ===> firefox-45.0.1 depends on: gettext->=0.10.38 -> gettext-0.19.7 ===> firefox-45.0.1 depends on: yasm-* - not found ===> Verifying install for yasm-* in devel/yasm ===> Looking for yasm-1.3.0.tgz in $PKG_PATH - ^C ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Here it never finds anything Then I do the following and it works: $ sudo pkg_delete quirks && make [...] ===> firefox-45.0.1 depends on: yasm-* - not found ===> Verifying install for yasm-* in devel/yasm ===> Looking for yasm-1.3.0.tgz in $PKG_PATH - found Link to /usr/ports/packages/amd64/cdrom/yasm-1.3.0.tgz Link to /usr/ports/packages/amd64/ftp/yasm-1.3.0.tgz ===> yasm-1.3.0 depends on: libiconv-* -> libiconv-1.14p3 ===> yasm-1.3.0 depends on: gettext->=0.10.38 -> gettext-0.19.7 ===> yasm-1.3.0 depends on: gettext-tools-* -> gettext-tools-0.19.7p0 ===> Verifying specs: c intl>=5 iconv>=6 ===> found c.86.0 intl.6.0 iconv.6.0 ===> Installing yasm-1.3.0 from /usr/ports/packages/amd64/all/ yasm-1.3.0: ok ===> Returning to build of firefox-45.0.1 ===> firefox-45.0.1 depends on: yasm-* -> yasm-1.3.0 ===> Verifying specs:....
