buildroot

package/google-breakpad: really fix the C++11 dependency

The C++11 build issue is still here since the C++11 is not complete in
gcc 4.7 [1]. So disable Google-breakpad for toolchains based on
gcc <= 4.7.

[1] https://gcc.gnu.org/gcc-4.7/cxx0x_status.html

Fixes:
http://autobuild.buildroot.net/results/c5e/c5e629f26bf6da369dff1e4588c16d2773173e9f

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>