Add some const qualifiers enabled by typeof_unqual change on copyObject

Hardcode typeof_unqual to __typeof_unqual__ for clang

Hardcode override of typeof_unqual for clang-for-bitcode

Make typeof and typeof_unqual fallback definitions work on C++11

Fixes for C++ typeof implementation

Fix additional fallthrough warnings from clang

Fix additional fallthrough warning

Enable -Wimplicit-fallthrough option for clang

test_cplusplusext: Add C++ pg_fallthrough test case

Use fallthrough attribute instead of comment

meson: allow disabling building/installation of static libraries.

meson: Refactor libpq targets variables

Change remaining StaticAssertStmt() to StaticAssertDecl()

Change StaticAssertVariableIsOfType to be a declaration

Rename AssertVariableIsOfType to StaticAssertVariableIsOfType

Fix accidentally cast away qualifiers

Detect if flags are needed for C++11 support

Remove redundant AssertVariableIsOfType uses

Remove more leftovers of AIX support

Fix PL/Python build on MSVC with older Meson