GCC is installed multiple times #24907
Description
#24599 introduced an import regression: GCC is installed multiple times:
jdemeyer@sardonis:~/sage-gcc$ grep 'Setting up build directory for gcc' logs/install.log
[gcc-7.2.0] Setting up build directory for gcc-7.2.0
[gcc-7.2.0] Setting up build directory for gcc-7.2.0
[gcc-7.2.0] Setting up build directory for gcc-7.2.0
Depends on #24867
CC: @embray
Component: build: configure
Author: Jeroen Demeyer
Branch: a682787
Reviewer: Volker Braun
Issue created by migration from https://trac.sagemath.org/ticket/24907