qt56-qtbase: error: integer value -1 is outside the valid range of values for this enumeration type

[ryandesign (Ryan Carsten Schmidt)]

On Mac OS X 10.7 MacPorts chooses to build qt56-qtbase with MacPorts clang-16 which fails because of these errors in src/corelib/global/qtypetraits.h:

error: integer value -1 is outside the valid range of values [0, 511] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 3] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 65535] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 1023] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 31] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 511] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 127] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 255] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 7] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 3] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
error: integer value -1 is outside the valid range of values [0, 3] for this enumeration type [-Wenum-constexpr-conversion]

I imagine this used to work, and then at some point the default MacPorts clang compiler was changed to a newer version that now considers this to be an error.

I already had MacPorts clang-3.7 installed so I tried building it with that instead and it worked.