Rebuild all other GCC packages against mpfr4, so they don't fail with:
Error loading shared library libmpfr.so.4: No such file or directory (needed by /usr/gcc4/libexec/gcc/x86_64-alpine-linux-musl/4.9.2/cc1)
[ci:skip-build]: won't finish in time
Related: 2b32ed3a48786fa151cad8f920e5d9997bee94ed in Alpine's aports.git
Explicitly depend on mpc1. Our generated gcc aports use the !tracedeps
option, so we need to explicitly set the libraries it depends on.
This has mostly not been an issue, as we are installing our gcc
packages together with Alpine's gcc package, which causes the libraries
to get installed anyway.
Fixes#236.
[ci:skip-build]: takes too long to build.
