Backported to p8 in "custom-gcc" style (initially introduced by alexey@)

Added ppc64le support.

Fixed profiledbootstrap build (by glebfm@).
Fixed build with libtool 2.4.6.

Built in gcc8 compatibility mode.

Rebuilt in precompat mode to prepare for gcc8 build.

Updated to redhat/gcc-7-branch r262599 (closes: #35089).
Synced with Fedora gcc 7.3.1-6.
Moved documentation for Fortran, Ada, and Go compilers from gcc7-doc
fortran-doc, gcc7-gnat-doc, and gcc7-go-doc subpackages.

Updated to redhat/gcc-7-branch r258210.
Synced with Fedora gcc 7.3.1-5.
Use --push-state --as-needed and --pop-state instead of --as-needed
Link libasan, liblsan, libtsan, and libubsan always with --no-as-needed.
mips64el: set default ABI to N64.

Do not add -Werror=stringop-overflow by default.
escalate-always-overflow.patch that used to
Werror=stringop-overflow introduced in 7.2.1-alt1 as its replacement

aarch64: packaged liblsan and libtsan (by Sergey Bolshakov).
arm, armh, aarch64: updated packaging of arch-specific header files

Updated to redhat/gcc-7-branch r257180.
Synced with Fedora gcc 7.3.1-4.
aarch64: fixed build.

Updated to redhat/gcc-7-branch r256767.
Synced with Fedora gcc 7.2.1-7 and Debian gcc-7 7.2.0-17.
Packaged gcc sources as separate package.
Dropped cxx knob from specfile.
Dropped all alternatives.

Updated to redhat/gcc-6-branch r244565.
Synced with Fedora gcc 6.3.1-2.
Fixed gnatmake's path to gcc (ALT#33003).
Packaged buildreq substitution config for libmpx6-devel-static.
Enabled java on aarch64.

Updated to redhat/gcc-6-branch r243852.
Synced with Fedora gcc 6.3.1-1 and Debian gcc-6 6.2.0-13.

Updated to redhat/gcc-5-branch 234777.

Moved liblto_plugin.so back into %_libexecdir.
Added executable bit to liblto_plugin.so.
Backported upstram fix:

Moved liblto_plugin.so into %_libdir.