In this PR, the reporter is complaining that forcing -static-libstdc++ 
and -static-libgcc during stage1 will also force it down to all 
subdirectories (gdb for instance).

There is some back and forth in the PR whether this is good or not.  I'm 
indifferent, but an alternative is to provide a flag 
--disable-stage1-static-libs to disable this behavior.

Tested on an x86-64 Linux system with static libraries and verifying 
that with --disable-stage1-static-libs we get an xgcc linked against 
shared libraries of libstdc++ and libgcc:

$ ldd xgcc
         linux-vdso.so.1 (0x00007ffe92084000)
         libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007fec11a06000)
         libm.so.6 => /lib64/libm.so.6 (0x00007fec116fd000)
         libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fec114e6000)
         libc.so.6 => /lib64/libc.so.6 (0x00007fec11120000)
         /lib64/ld-linux-x86-64.so.2 (0x0000557117206000)

I also verified that without the flag or with 
--enable-stage1-static-libs we get no such shared libraries.

Again, I'm agnostic here.  We can just as easily close the PR and tell 
users to specify --with-stage1-libs to override the static linking, as 
I've mentioned in the PR.

OK for trunk?