Another C++ strictness fix

Pango Bug 602408 - Invalid C++ code breaks compile with Sun C++ Compiler
(Error: A union member cannot have a user-defined assignment operator)

According to the bug:

C++ Programming Language by Bjarne Stroustrup: Chapter 10.4.12 forbids
explicitly using of union members with constructors, destructors or assignment
operations.

So we use a set() method instead of the assignment operator.  Ugly, but hey,
that's life.

src/hb-open-type-private.hh

@@ -262,7 +262,7 @@ _hb_sanitize_edit (SANITIZE_ARG_DEF,
 #define NEUTER(Var, Val) \
 	(SANITIZE_OBJ (Var) && \
 	 _hb_sanitize_edit (SANITIZE_ARG, CONST_CHARP(&(Var)), sizeof (Var)) && \
-	 ((Var) = (Val), true))
+	 ((Var).set (Val), true))
 
 
 /* Template to sanitize an object. */
@@ -349,7 +349,7 @@ struct Sanitizer
 #define _DEFINE_INT_TYPE1_UNALIGNED(NAME, TYPE, BIG_ENDIAN, BYTES) \
   struct NAME \
   { \
-    inline NAME& operator = (TYPE i) { (TYPE&) v = BIG_ENDIAN (i); return *this; } \
+    inline NAME& set (TYPE i) { (TYPE&) v = BIG_ENDIAN (i); return *this; } \
     inline operator TYPE(void) const { return BIG_ENDIAN ((TYPE&) v); } \
     inline bool operator== (NAME o) const { return (TYPE&) v == (TYPE&) o.v; } \
     inline bool sanitize (SANITIZE_ARG_DEF) { \
@@ -363,7 +363,7 @@ struct Sanitizer
 #define DEFINE_INT_TYPE1(NAME, TYPE, BIG_ENDIAN, BYTES) \
   struct NAME \
   { \
-    inline NAME& operator = (TYPE i) { BIG_ENDIAN##_put_unaligned(v, i); return *this; } \
+    inline NAME& set (TYPE i) { BIG_ENDIAN##_put_unaligned(v, i); return *this; } \
     inline operator TYPE(void) const { return BIG_ENDIAN##_get_unaligned (v); } \
     inline bool operator== (NAME o) const { return BIG_ENDIAN##_cmp_unaligned (v, o.v); } \
     inline bool sanitize (SANITIZE_ARG_DEF) { \
@@ -388,7 +388,7 @@ DEFINE_INT_TYPE (LONG,	  , 32);	/* 32-bit signed integer. */
 struct Tag : ULONG
 {
   inline Tag (const Tag &o) { *(ULONG*)this = (ULONG&) o; }
-  inline Tag (uint32_t i) { *(ULONG*)this = i; }
+  inline Tag (uint32_t i) { (*(ULONG*)this).set (i); }
   inline Tag (const char *c) { *(ULONG*)this = *(ULONG*)c; }
   inline bool operator== (const char *c) const { return *(ULONG*)this == *(ULONG*)c; }
   /* What the char* converters return is NOT nul-terminated.  Print using "%.4s" */

src/hb-ot-layout-common-private.hh

@@ -328,7 +328,7 @@ struct CoverageFormat1
     if (HB_UNLIKELY (glyph_id > 0xFFFF))
       return NOT_COVERED;
     GlyphID gid;
-    gid = glyph_id;
+    gid.set (glyph_id);
     // TODO: bsearch
     unsigned int num_glyphs = glyphArray.len;
     for (unsigned int i = 0; i < num_glyphs; i++)