This reverts commit decc7ed888.
This compilation options (-fpermissive) is no longer needed,
as the code that caused the warnings on GCC <7 is no longer
present.
The reason this error was GCC bug #56480 [1], which disallowed
the following (valid, in C++11) syntax:
template<> struct namespace_a::namespace_b::a_struct<TYPE>
{...}
And instead insisted on:
namespace namespace_a {
namespace namespace_b {
template<> struct a_struct<TYPE>
{...}
}
}
[1]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480
f5144eb5cf