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We tried to use APM drop gcc, but it would crash pretty quickly as well, with the message "error: gmp.h header not found". Unfortunately, reinstalling gmp and gmp-devel packages did not solve this problem.
With the freshly installed Fedora 21, and fully installed gcc package from Fedora repos, we tried to build gcc again. This time it broke while trying to build "libgomp". Checking the build logs showed that the problem is: "/usr/bin/ld: cannot find -lgcc_s". The file "libgcc_s" is present in /usr/lib64/, which is the default. Somehow, the linker still doesn't find it. On the following screenshot, you can see the building error (left), the build log with the exact error (middle), and the corresponding code within the configure file (located at "rpmbuild/BUILD/gcc-4.9.2-20150212/libgomp/").
are installing Fedora 21 on one of the builders to have a clean install with Fedora gcc. Then we will try to build our MultiLib capable gcc on that system. When succeeded, we will install our gcc on a LEAP builder, change the spec file for gcc to point towards that MultiLib capable gcc, and produce the final version of our gcc.