Make sure that values of absolute symbols fit in 16 bits.

tools/winebuild/build.h

@@ -63,7 +63,7 @@ typedef struct
 
 typedef struct
 {
-    int value;
+    unsigned short value;
 } ORD_ABS;
 
 typedef struct

tools/winebuild/parser.c

@@ -355,6 +355,11 @@ static int parse_spec_equate( ORDDEF *odp, DLLSPEC *spec )
         error( "Expected number value, got '%s'\n", token );
         return 0;
     }
+    if (value < -0x8000 || value > 0xffff)
+    {
+        error( "Value %d for absolute symbol doesn't fit in 16 bits\n", value );
+        value = 0;
+    }
     odp->u.abs.value = value;
     return 1;
 }