Merged PR 5181334: OS build fixes on top of abf8805

til::color
It turns out that clang/gcc are okay with the anonymous
struct, but the CL we use in Windows was not.

src/inc/til/color.h

@@ -21,6 +21,9 @@ namespace til // Terminal Implementation Library. Also: "Today I Learned"
         // Here, we leverage the spec-legality of using unions for type conversions and the
         // overlap of four uint8_ts and a uint32_t to make the conversion very obvious to
         // both compilers.
+#pragma warning(push)
+        // CL will complain about the both nameless and anonymous struct.
+#pragma warning(disable : 4201)
         union
         {
             struct
@@ -33,6 +36,7 @@ namespace til // Terminal Implementation Library. Also: "Today I Learned"
             };
             uint32_t abgr;
         };
+#pragma warning(pop)
 
         constexpr color() noexcept :
             r{ 0 },