What modules was your distribution of Apache built with?

To determine the modules your Windows Apache distribution was built/compiled with, run the command:
httpd -l
or
apache.exe -l

Trimmed down list of Apache modules

Some common core modules:
mod_so: Enable the loading of executable code and modules into the server at start-up or restart time.
For example, in your httpd.conf
LoadModule php4_module "E:/Inetpub/php4/php4apache2.dll"

mpm_winnt: This Multi-Processing Module is optimized for Windows NT.

Some common loaded modules:
mod_access.so: Provides access control based on client hostname, IP address ... (Apache prior to 2.1).
mod_actions.so: This module provides for executing CGI scripts based on media type or request method.
mod_alias.so: Provides for mapping different parts of the host file system in the document tree and for URL redirection.
mod_asis.so: Sends files that contain their own HTTP headers.
mod_auth.so: User authentication using text files ... (Apache prior to 2.1).
mod_auth_basic.so: Basic authentication (Apache 2.1 and later).
mod_auth_digest.so: User authentication using MD5 Digest Authentication.
mod_authn_default.so: Authentication fallback module (Apache 2.1 and later).
mod_authn_file.so: User authentication using text files (Apache 2.1 and later).
mod_authz_default.so: Authorization fallback module (Apache 2.1 and later).
mod_authz_groupfile.so: Group authorization using plaintext files (Apache 2.1 and later).
mod_authz_host.so: Group authorizations based on host (name or IP address) (Apache 2.1 and later).
mod_authz_user.so: User Authorization (Apache 2.1 and later).
mod_autoindex.so: Generates directory indexes, automatically.
mod_cgi.so: Execution of CGI scripts.
mod_deflate.so: Compress content before it is delivered to the client.
mod_dir.so: Provides for "trailing slash" redirects and serving directory index files.
mod_env.so: Modifies the environment which is passed to CGI scripts and SSI pages.
mod_include.so: Server-parsed html documents (Server Side Includes).
mod_isapi.so: ISAPI Extensions within Apache for Windows.
mod_log_config.so: Logging of the requests made to the server.
mod_mime.so: Associates the requested filename's extensions with the file's behavior (handlers and filters) and content (mime-type, language, character set and encoding).
mod_negotiation.so: Provides for content negotiation.
mod_rewrite.so: Provides a rule-based rewriting engine to rewrite requested URLs on the fly.
mod_setenvif.so: Allows the setting of environment variables based on characteristics of the request.
mod_ssl.so: Strong cryptography using the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols.
 

Sometimes (was loaded by default with some distribution but not others):
mod_dav.so: Distributed Authoring and Versioning (WebDAV) functionality (xampp).
mod_dav_fs.so: file system provider for mod_dav (xampp).
mod_info.so: Provides a comprehensive overview of the server configuration (xampp).
mod_ldap.so: LDAP connection pooling and result caching services for use by other LDAP modules (xampp).
mod_log_rotate.so: Log rotation build specific (ApacheLounge).
mod_status.so: Provides information on server activity and performance (xampp).
See potential bug report: Apache: PHP 4 using mod_rewrite getting blank page
mod_autoindex_color.so: Generates directory indexes, automatically, similar to the Unix ls command or the Win32 dir shell command in color (xampp).

 

Complete list of Apache 2.0.x modules

Complete list of Apache 2.2.x modules