* gnu/packages/commencement.scm (gcc-core-mesboot1): New variable. (gmp-boot, mpfr-boot, mpc-boot): Scheme-only bootstrap. * gnu/packages/patches/gcc-boot-4.6.4.patch: New file. * gnu/packages/patches/gcc-boot-4.7.4.patch: Remove. * gnu/local.mk (dist_patch_DATA): Update.