The files for GMP, MPFR and MPC in ftp://gcc.gnu.org/pub/gcc/infrastructure are not gpg-signed. Since these files are required to build gcc, it would be prudent to add them.
MPFR and GMP have signatures at their upstream sites which could be added. MPC is not currently distributed with signatures upstream. configure: error: Building GCC requires GMP 4.2+, MPFR 2.3.1+ and MPC 0.8.0+. Try the --with-gmp, --with-mpfr and/or --with-mpc options to specify their locations. Source code for these libraries can be found at their respective hosting sites as well as at ftp://gcc.gnu.org/pub/gcc/infrastructure/. See also http://gcc.gnu.org/install/prerequisites.html for additional info. If you obtained GMP, MPFR and/or MPC from a vendor distribution package, make sure that you have installed both the libraries and the header files. They may be located in separate packages. -- Summary: untrusted sources in pub/gcc/infrastructure Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: other AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: bjg at gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43777