Both apr and apr-util are required to build passenger.

The are not neccessarily installed in the same --prefix
(see ./configure)
(note, the apu-1-config does not accept the --cppflags option

With my pgollucci@apache.org HTTPD PMC hat on:

Technicallly, this is still wrong, this should be using apxs alone,
but that would have required me to refactor this and I did not have
time at the moment.   For an example of the correct way to do this,
see the apreq (libapreq2) httpd module (c-binding portion).
[apreq-dev@httpd.apache.org]

Note, Eventually, httpd will have an httpd-config similiar to
gnome-config, neon-config, serf-config, etc.... at which point
it should switch to that.

Rakefile

@@ -37,6 +37,7 @@ APXS2.nil? and raise "Could not find 'apxs' or 'apxs2'."
 APACHE2CTL.nil? and raise "Could not find 'apachectl' or 'apache2ctl'."
 HTTPD.nil? and raise "Could not find the Apache web server binary."
 APR_FLAGS.nil? and raise "Could not find Apache Portable Runtime (APR)."
+APU_FLAGS.nil? and raise "Could not find Apache Portable Runtime Utility (APU)."
 
 CXX = "g++"
 # _GLIBCPP__PTHREADS is for fixing Boost compilation on OpenBSD.
@@ -120,7 +121,7 @@ end
 ##### Apache module
 
 class APACHE2
-	CXXFLAGS = "-I.. -fPIC #{OPTIMIZATION_FLAGS} #{APR_FLAGS} #{APXS2_FLAGS} #{CXXFLAGS}"
+    CXXFLAGS = "-I.. -fPIC #{OPTIMIZATION_FLAGS} #{APR_FLAGS} #{APU_FLAGS} #{APXS2_FLAGS} #{CXXFLAGS}"
 	OBJECTS = {
 		'Configuration.o' => %w(Configuration.cpp Configuration.h),
 		'Bucket.o' => %w(Bucket.cpp Bucket.h),
@@ -202,7 +203,7 @@ end
 class TEST
 	CXXFLAGS = "#{::CXXFLAGS} -DTESTING_SPAWN_MANAGER -DTESTING_APPLICATION_POOL "
 
-	AP2_FLAGS = "-I../ext/apache2 -I../ext -Isupport #{APR_FLAGS}"
+    AP2_FLAGS = "-I../ext/apache2 -I../ext -Isupport #{APR_FLAGS} #{APU_FLAGS}"
 	AP2_OBJECTS = {
 		'CxxTestMain.o' => %w(CxxTestMain.cpp),
 		'MessageChannelTest.o' => %w(MessageChannelTest.cpp

bin/passenger-install-apache2-module

@@ -48,6 +48,7 @@ class Installer
 		Dependencies::Apache2,
 		Dependencies::Apache2_DevHeaders,
 		Dependencies::APR_DevHeaders,
+		Dependencies::APU_DevHeaders,
 		Dependencies::FastThread,
 		Dependencies::Rack
 	]

lib/passenger/dependencies.rb

@@ -216,7 +216,7 @@ module Dependencies # :nodoc: all
 			end
 		elsif RUBY_PLATFORM =~ /freebsd/
 			dep.install_command = "make -C /usr/ports/www/apache22 install"
-			dep.provides = [Apache2_DevHeaders, APR_DevHeaders]
+			dep.provides = [Apache2_DevHeaders, APR_DevHeaders, APU_DevHeaders]
 		end
 		dep.website = "http://httpd.apache.org/"
 	end
@@ -270,6 +270,15 @@ module Dependencies # :nodoc: all
 		dep.website = "http://httpd.apache.org/"
 		dep.website_comments = "APR is an integrated part of Apache."
 	end
+
+	APU_DevHeaders = Dependency.new do |dep|
+		dep.name = "Apache Portable Runtime Utility (APR) development headers"
+		dep.define_checker do |result|
+			result.found(APU_CONFIG)
+		end
+		dep.website = "http://httpd.apache.org/"
+		dep.website_comments = "APR Utility is an integrated part of Apache."
+	end
 
 	FastThread = Dependency.new do |dep|
 		dep.name = "fastthread"

lib/passenger/platform_info.rb

@@ -164,6 +164,42 @@ def self.determine_apr_info
 			return [flags, libs]
 		end
 	end
+
+	def self.find_apu_config
+		if env_defined?('APU_CONFIG')
+			apr_config = ENV['APU_CONFIG']
+		elsif RUBY_PLATFORM =~ /darwin/ && HTTPD == "/usr/sbin/httpd"
+			# If we're on MacOS X, and we're compiling against the
+			# default provided Apache, then we'll want to query the
+			# correct 'apu-1-config' command. However, that command
+			# is not in $PATH by default. Instead, it lives in
+			# /Developer/SDKs/MacOSX*sdk/usr/bin.
+			sdk_dir = Dir["/Developer/SDKs/MacOSX*sdk"].sort.last
+			if sdk_dir
+				apu_config = "#{sdk_dir}/usr/bin/apu-1-config"
+				if !File.executable?(apu_config)
+					apu_config = nil
+				end
+			end
+		else
+			apu_config = find_command('apu-1-config')
+			if apu_config.nil?
+				apu_config = find_command('apu-config')
+			end
+		end
+		return apu_config
+	end
+
+	def self.determine_apu_info
+		if APU_CONFIG.nil?
+			return nil
+		else
+			flags = `#{APU_CONFIG} --includes`.strip
+			libs = `#{APU_CONFIG} --link-ld`.strip
+			flags.gsub!(/-O\d? /, '')
+			return [flags, libs]
+		end
+	end
 
 	def self.determine_multi_arch_flags
 		if RUBY_PLATFORM =~ /darwin/ && !HTTPD.nil?
@@ -269,12 +305,14 @@ def self.find_command(name)
 	HTTPD = find_httpd
 	# The absolute path to the 'apr-config' or 'apr-1-config' executable.
 	APR_CONFIG = find_apr_config
+	APU_CONFIG = find_apu_config
 
 	# The C compiler flags that are necessary to compile an Apache module.
 	APXS2_FLAGS = determine_apxs2_flags
 	# The C compiler flags that are necessary for programs that use APR.
 	APR_FLAGS, APR_LIBS = determine_apr_info
-
+    APU_FLAGS, APU_LIBS = determine_apu_info
+
 	# The C compiler flags that are necessary for building binaries in the same architecture(s) as Apache.
 	MULTI_ARCH_FLAGS = determine_multi_arch_flags