I am getting this issue when running
httpd -t
httpd: Syntax error on line 545 of /private/etc/apache2/httpd.conf: Syntax error on line 1 of /private/etc/apache2/other/passenger.conf: Cannot load /Users/sbaidon/.rvm/gems/ruby-2.2.5/gems/passenger-5.3.5/b
uildout/apache2/mod_passenger.so into server: dlopen(/Users/sbaidon/.rvm/gems/ruby-2.2.5/gems/passenger-5.3.5/buildout/apache2/mod_passenger.so, 10): no suitable image found. Did find:\n\t/Users/sbaidon/.rv
m/gems/ruby-2.2.5/gems/passenger-5.3.5/buildout/apache2/mod_passenger.so: code signature in (/Users/sbaidon/.rvm/gems/ruby-2.2.5/gems/passenger-5.3.5/buildout/apache2/mod_passenger.so) not valid for use in p
rocess using Library Validation: mapped file has no cdhash, completely unsigned? Code has to be at least ad-hoc signed.\n\t/Users/sbaidon/.rvm/gems/ruby-2.2.5/gems/passenger-5.3.5/buildout/apache2/mod_passen
ger.so: stat() failed with errno=22
Passenger installation is just fine.
I ran into this too: the issue is that the built-in httpd that comes with macOS Mojave has Library Validation turned on, which means any modules it loads must be properly signed. Unfortunately, mod_passenger.so is not signed, so loading fails. Actually, a lot of people are having this problem with loading Apache modules on macOS Mojave (especially during the beta), some example references:
https://github.com/GrahamDumpleton/mod_wsgi/issues/357
https://github.com/phpredis/phpredis/issues/1406
I believe it's possible to set up a plist somewhere to give an entitlement to httpd to disable library validation (com.apple.security.cs.disable-library-validation) as described at https://developer.apple.com/documentation/security/com_apple_security_cs_disable-library-validation. For instance, here's a recent WebKit patch where they add it to allow plugin loading: https://bugs.webkit.org/show_bug.cgi?id=183252. Similarly, here's the Mozilla people talking about how they need to enable this (and other) properties: https://bugzilla.mozilla.org/show_bug.cgi?format=default&id=1470597.
Unfortunately, I don't do macOS development (I just do development on macOS) and I have absolutely no idea how to apply it to the built-in Apache, I'm sorry.
At this point I'm kind of sick of every major macOS update nerfing all my httpd settings and generally being a pain (it's infrequent but it's still annoying), so I'm doing what I should have done years ago: stop using the built-in httpd that comes with OS/X and just use Homebrew httpd.
Here's some instructions I found regarding setting up Homebrew httpd (and disabling the built-in macOS httpd), it's pretty straightforward and you don't have to follow all of the directions about multiple PHP versions etc: https://getgrav.org/blog/macos-mojave-apache-multiple-php-versions
If someone can figure out how to disable Library Validation in the built-in httpd, or if there is some way to provide signing on mod_passenger.so (seems unlikely since both the Homebrew and gem passenger need to be buildable from source), you don't need to junk the built-in httpd. But I personally think the best solution is to move away from it entirely and use the Homebrew version instead.
For anyone having this issue or any issue with library validation in macOS Mojave, I found an incredibly easy fix to disable it. https://github.com/mologie/macos-disable-library-validation
This is fixed in macOS 10.14.4