Fix theoretically possible overflow

https://bugzilla.redhat.com/show_bug.cgi?id=884000
Fix export-symbols on Windows
Remove old cruft
Fix test when EXEEXT is not empty
Fix bug with rule W5

Test case added.

This was discovered by running against the Unicode test suite.

https://github.com/behdad/fribidi-vs-unicode
Fix rule X8 when paragraph-separator is present

As discovered by:
https://github.com/behdad/fribidi-vs-unicode

All passing now.
Fix misprint
Invoke pkg-config macros properly
Try to help some builds (on Windows, no less)
Revert "Try to help some builds (on Windows, no less)"

This reverts commit 7c3963fc8e852e7ed7000accb326f5f178196c41.

Previous commit broke my build.  Clearly more work needs to be done in
this area...
Port test suite to automake 1.13
0.19.6
Merge tag 'tags/0.19.6'

0.19.6

# gpg: error loading `iconv.dll': The specified module could not be found.
#
# gpg: please see http://www.gnupg.org/download/iconv.html for more information
# gpg: keyblock resource `c:/Users/Matt/.gnupg\pubring.gpg': file open error
# gpg: Signature made 12/07/13 07:57:50 using DSA key ID D3531115
# gpg: Can't check signature: public key not found
Updated VS project for changes in version 0.19.6.

Required adding back in a .def module definition file due to the removal
of dllexport from fribidi sources. The .def file included with fribidi
doesnt work as it does not specify the 'EXPORTS' directive so a custom
.def file was created.