Fixes compatibility with Ruby apps whose Gemfile.lock depends on base64

CHANGELOG

@@ -5,6 +5,7 @@ Release 6.0.24 (Not yet released)
  * [Enterprise] Fix a memory corruption-related crash that could occur during rolling restarting.
  * [Ubuntu] Add packages for Ubuntu 24.10 "oracular".
  * [Ruby] Specify rackup version to avoid broken 1.0 gem. Closes GH-2559.
+ * Fixes compatibility with Ruby apps whose Gemfile.lock depends on base64.
  * Upgrades Boost from 1.85 -> 1.86.
  * Updated various library versions used in precompiled binaries (used for e.g. gem installs):
    - ccache 4.10.1 -> 4.10.2

src/ruby_supportlib/phusion_passenger/utils.rb

@@ -23,8 +23,6 @@
 #  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 #  THE SOFTWARE.
 
-require 'base64'
-
 module PhusionPassenger
 
   # Utility functions.
@@ -182,19 +180,11 @@ def install_options_as_ivars(object, options, *keys)
       end
     end
 
-    if Base64.respond_to?(:strict_encode64)
-      def base64(data)
-        Base64.strict_encode64(data)
-      end
-    else
-      # Base64-encodes the given data. Newlines are removed.
-      # This is like `Base64.strict_encode64`, but also works
-      # on Ruby 1.8 which doesn't have that method.
-      def base64(data)
-        result = Base64.encode64(data)
-        result.delete!("\n")
-        result
-      end
+    # Returns a base64 encoded string without line breaks and padding.
+    # Like Base64.strict_encode64, but without a dependency on the
+    # 'base64' library/gem.
+    def base64(data)
+      [data].pack("m0")
     end
 
     # Returns a string which reports the backtraces for all threads,