bugfix: sf.net #899 trim( wstring ) causes crash if string is single space

- In fb_wstr_CalcDiff() the original expression is optimized with a SHR expression due the divide by unsigned power of 2.  This doesn't work for negative values.
- Casting to intptr_t should not be needed as the pointer arithmetic alone should be sufficient to calculate distance betwee related pointers

Author: jayrm

changelog.txt

@@ -15,6 +15,7 @@ Version 1.07.0
 - sf.net #897: length of literal wstring is miscalculated at compile time.  Compile time evaluation of len(!"\u1234") was using the internal escaped string length instead of the actual codepoint length
 - github #137: Final -Wl flag takes precedence over previous.  fbc now passes down all options from all -Wa, -Wc, and -Wl flags (William Breathitt Gray)
 - github #138: rtlib: freebsd: Fix deprecated use of VM_METER to use VM_TOTAL (William Breathitt Gray)
+- sf.net #899: trim( wstring ) causes crash if string is single space
 
 
 Version 1.06.0

src/rtlib/fb_unicode.h

@@ -126,7 +126,7 @@ typedef uint8_t  UTF_8;
 /* Calculate the number of characters between two pointers. */
 static __inline__ ssize_t fb_wstr_CalcDiff( const FB_WCHAR *ini, const FB_WCHAR *end )
 {
-	return ((intptr_t)end - (intptr_t)ini) / sizeof( FB_WCHAR );
+	return end - ini;
 }
 
 static __inline__ FB_WCHAR *fb_wstr_AllocTemp( ssize_t chars )