Add Watcom C/C++ support.

* include/freetype/config/integer-types.h: Make sure `long long` is
used then available.
* include/freetype/internal/ftcalc.h (FT_MSB): Add Watcom C/C++ pragma.

include/freetype/config/integer-types.h

@@ -221,9 +221,10 @@
 #define FT_INT64   __int64
 #define FT_UINT64  unsigned __int64
 
-#elif defined( __WATCOMC__ )   /* Watcom C++ */
+#elif defined( __WATCOMC__ ) && __WATCOMC__ >= 1100  /* Watcom C++ */
 
-  /* Watcom doesn't provide 64-bit data types */
+#define FT_INT64   long long int
+#define FT_UINT64  unsigned long long int
 
 #elif defined( __MWERKS__ )    /* Metrowerks CodeWarrior */
 

include/freetype/internal/ftcalc.h

@@ -408,6 +408,19 @@ FT_BEGIN_HEADER
 
 #endif
 
+#elif defined( __WATCOMC__ ) && defined( __386__ )
+
+  extern __inline FT_Int32
+  FT_MSB_i386( FT_UInt32  x );
+
+#pragma aux FT_MSB_i386 =     \
+  "bsr eax, eax"              \
+  parm [eax] nomemory         \
+  value [eax]                 \
+  modify exact [eax] nomemory;
+
+#define FT_MSB( x )  FT_MSB_i386( x )
+
 #elif defined( __DECC ) || defined( __DECCXX )
 
 #include <builtins.h>