math: disable const union members on GCC prior to 4.6.

src/lol/math/vector.h

@@ -28,6 +28,14 @@
 namespace lol
 {
 
+/* Some compilers do not support const members in anonymous unions. So
+ * far, GCC (>= 4.6), CLang (3.0) and Visual Studio (>= 2010) appear to
+ * work properly. */
+#undef LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS
+#if defined __GNUC__ && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6))
+#   define LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS 1
+#endif
+
 #define DECLARE_VECTOR_TYPEDEFS(tname, suffix) \
     template <typename T> struct tname; \
     typedef tname<half> f16##suffix; \
@@ -128,6 +136,9 @@ template <typename T> struct BVec2
         struct { T r, g; };
         struct { T s, t; };
 
+#if LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS
+#   define const /* disabled */
+#endif
         XVec2<T,0x00> const xx, rr, ss;
         XVec2<T,0x01> const xy, rg, st; /* lvalue */
         XVec2<T,0x10> const yx, gr, ts; /* lvalue */
@@ -158,6 +169,9 @@ template <typename T> struct BVec2
         XVec4<T,0x1101> const yyxy, ggrg, ttst;
         XVec4<T,0x1110> const yyyx, gggr, ttts;
         XVec4<T,0x1111> const yyyy, gggg, tttt;
+#if LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS
+#   undef const
+#endif
     };
 };
 
@@ -287,6 +301,9 @@ template <typename T> struct BVec3
         struct { T r, g, b; };
         struct { T s, t, p; };
 
+#if LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS
+#   define const /* disabled */
+#endif
         XVec2<T,0x00> const xx, rr, ss;
         XVec2<T,0x01> const xy, rg, st; /* lvalue */
         XVec2<T,0x02> const xz, rb, sp; /* lvalue */
@@ -406,6 +423,9 @@ template <typename T> struct BVec3
         XVec4<T,0x2220> const zzzx, bbbr, ppps;
         XVec4<T,0x2221> const zzzy, bbbg, pppt;
         XVec4<T,0x2222> const zzzz, bbbb, pppp;
+#if LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS
+#   undef const
+#endif
     };
 };
 
@@ -468,6 +488,9 @@ template <typename T> struct BVec4
         struct { T r, g, b, a; };
         struct { T s, t, p, q; };
 
+#if LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS
+#   define const /* disabled */
+#endif
         XVec2<T,0x00> const xx, rr, ss;
         XVec2<T,0x01> const xy, rg, st; /* lvalue */
         XVec2<T,0x02> const xz, rb, sp; /* lvalue */
@@ -806,6 +829,9 @@ template <typename T> struct BVec4
         XVec4<T,0x3331> const wwwy, aaag, qqqt;
         XVec4<T,0x3332> const wwwz, aaab, qqqp;
         XVec4<T,0x3333> const wwww, aaaa, qqqq;
+#if LOL_NO_CONST_MEMBERS_IN_ANONYMOUS_UNIONS
+#   undef const
+#endif
     };
 };