Fixing C4146 warning

Rebased-By: Wladimir J. van der Laan <laanwj@gmail.com>

src/script/script.h

@@ -304,7 +304,7 @@ private:
       // If the input vector's most significant byte is 0x80, remove it from
       // the result's msb and return a negative.
       if (vch.back() & 0x80)
-          return -(result & ~(0x80ULL << (8 * (vch.size() - 1))));
+          return -((int64_t)(result & ~(0x80ULL << (8 * (vch.size() - 1)))));
 
       return result;
     }

src/util.cpp

@@ -618,7 +618,7 @@ void ShrinkDebugFile()
     {
         // Restart the file with some of the end
         std::vector <char> vch(200000,0);
-        fseek(file, -vch.size(), SEEK_END);
+        fseek(file, -((long)vch.size()), SEEK_END);
         int nBytes = fread(begin_ptr(vch), 1, vch.size(), file);
         fclose(file);