Toolchain+LibM: Make C++ standard library math functions available

With this fixed we get libstdc++v3's aliases for C99 math functions
in the std namespace. Unfortunately for this to work the toolchain
needs to be rebuilt.

The good news are that this by itself does not require a toolchain
rebuild just yet.

Userland/Libraries/LibM/math.h

@@ -74,7 +74,7 @@ __BEGIN_DECLS
 #define isless(x, y) __builtin_isless((x), (y))
 #define islessequal(x, y) __builtin_islessequal((x), (y))
 #define islessgreater(x, y) __builtin_islessgreater((x), (y))
-#define isunordered(x, y) __builtin_isunoredered((x), (y))
+#define isunordered(x, y) __builtin_isunordered((x), (y))
 
 #define DOUBLE_MAX ((double)0b0111111111101111111111111111111111111111111111111111111111111111)
 #define DOUBLE_MIN ((double)0b0000000000010000000000000000000000000000000000000000000000000000)