OK, Sourceforge is back. So you have Apache 2.2.21 w/ OpenSSL 1.0.0e (ouch).
Here's my suggestion:
First (important) make a backup of the files you will be replacing;
Download the OpenSSL update for 2.2.29 from Apache Haus: https://www.apachehaus.com/cgi-bin/download.plx
Replace the files in your Apache with the ones in the zip file.
If it fails, replace the files with the ones you made a backup of.
I guess you're simply out of luck short of updating your xampp.
This should work just fine however. Since the Apache in xampp 1.7.5 came with OpenSSL 1.0.0e, and the php included uses 0.9.8r and php is loaded as a module, you could never have used the php_openssl extension anyway. This will not change.