[Rd] Bug in R 2.7 for over long lines

[Soeren Sonnenburg]

While trying to fix swig & R2.7 I actually discovered that there is a
bug in R 2.7 causing a crash (so R & swig might actually work):

the bug is in ./src/main/gram.c  line 3038:

            } else { /* over-long line */
fixthis --> char *LongLine = (char *) malloc(nc);
            if(!LongLine)
                error(_("unable to allocate space for source line %d"), xxlineno);
            strncpy(LongLine, (char *)p0, nc);
 bug -->    LongLine[nc] = '\0';
            SET_STRING_ELT(source, lines++,
                       mkChar2((char *)LongLine));
            free(LongLine);

note that LongLine is only nc chars long, so the LongLine[nc]='\0' might
be an out of bounds write. the fix would be to do

            char *LongLine = (char *) malloc(nc+1);

in line 3034

Please fix and thanks to dirk for the debian r-base-dbg package!

Soeren