The register keyword is deprecated in C++11

[Sebastian Huber]

The following code gives a warning with GCC and -std=c++17:

void f(void)
{
  register int i;
}

test.cc: In function ‘void f()’:
test.cc:3:15: warning: ISO C++1z does not allow ‘register’ storage class specifier [-Wregister]
  register int i;
               ^

Remove the use of the register keyword at least in the public header files for C++ compatibility.

[Sebastian Huber <sebastian.huber@…>]

In f35c3be9/rtems:

Remove register keyword from public header files

The following code

void f(void)
{

register int i;

}

gives a warning with GCC and -std=c++17

test.cc: In function ‘void f()’:
test.cc:3:15: warning: ISO C++1z does not allow ‘register’ storage class
specifier [-Wregister]

register int i;

and clang with -std=c++14

test.cc:3:3: warning: 'register' storage class specifier is deprecated
and incompatible with C++1z [-Wdeprecated-register]

register int i;

1 warning generated.

Remove the use of the register keyword at least in the public header
files for C++ compatibility.

Close #3397.