Name mangling is an implementation detail to fit into UNIX linker design space, not the same approach as other compiled languages with modules, with their own linker.
Also name mangling (which in this case would simply be appending the namespace name to the identifier) would be trivially implementable in C.
In fact on some targets the assembler name of identifiers doesn't always match the C name already.
Although as someone almost always explicitly qualifies names,
typing foo_bar is not very different from foo::bar; the only minor advantages are that you do not have to use foo:: inside the implementation of foo itself and the ability to use aliases.
