Makefile.PL: optionally use Alien::librdkafka

Makefile.PL

@@ -5,24 +5,109 @@ use warnings;
 use Config;
 use ExtUtils::MakeMaker;
 use ExtUtils::PkgConfig;
+use Text::ParseWords qw(shellwords);
 
 use constant LIBRDKAFKA_MIN_VERSION => "1.0.0";
 
+# Fix for OSX:
+$ENV{PKG_CONFIG_PATH} .= ':/usr/local/opt/openssl/lib/pkgconfig/'
+    if $^O eq 'darwin';
+# rdkafka.pc has libcrypto as a required dependency, so
+# if libcrypto can't be found, pkg-config won't return
+# values for rdkafka.
+# Problem: in OSX, the default libcrypto lives in a non-default
+# location, meaning that without some tweaking like above,
+# we never get values for rdkafka.
+
+sub prepare_lddlflags {
+    my ($lddlflags) = @_;
+    # `-Wl,-z,now` breaks static linking to librdkafka.a, and
+    # the perl you get from pacman in ArchLinux has that by default
+    # in lddlflags.
+    # Similar with --as-needed
+    $lddlflags =~ s<,-z[,= ]now><>g;
+    $lddlflags =~ s<,--as-needed\b><>g;
+    $lddlflags =~ s<-Wl\s>< >g; # did we remove every linker option?
+    return $lddlflags;
+}
+
+my @archive_after;
+my $makemaker_libs = [];
+my $makemaker_inc  = '';
+
+my $ccflags    = $Config{'ccflags'} // '';
+my $lddlflags  = prepare_lddlflags($Config{'lddlflags'} // '');
+
 # If you have a local librdkafka installation and you want to use that instead
 # of the system-wide, do something like:
 # PKG_CONFIG_PATH=/usr/local/lib/pkgconfig perl Makefile.PL
 # or whatever is the actual installation path
-my %rdkafka = ExtUtils::PkgConfig->find('rdkafka');
+eval {
+    my %rdkafka = ExtUtils::PkgConfig->find('rdkafka');
+    $makemaker_libs = '-lpthread -lrdkafka';
+    $lddlflags    .= ' ' . $rdkafka{libs};
+    $makemaker_inc = $rdkafka{cflags};
+    warn sprintf(
+        "WARNING: Installed librdkafka version %s is lower than tested %s",
+        $rdkafka{modversion},
+        LIBRDKAFKA_MIN_VERSION
+    ) if $rdkafka{modversion} lt LIBRDKAFKA_MIN_VERSION;
+
+    print "Compiling Net::Kafka with librdkafka $rdkafka{modversion}\n\n";
+
+    1;
+} or do {
+    my $pkg_config_error = $@ || 'Zombie error';
 
-warn sprintf(
-    "WARNING: Installed librdkafka version %s is lower than tested %s",
-    $rdkafka{modversion},
-    LIBRDKAFKA_MIN_VERSION
-) if $rdkafka{modversion} lt LIBRDKAFKA_MIN_VERSION;
+    eval {
+        require Alien::librdkafka;
+        $makemaker_inc .= ' ' . Alien::librdkafka->cflags;
+        my $libs = Alien::librdkafka->install_type eq 'share'
+             ? Alien::librdkafka->libs_static || Alien::librdkafka->libs
+             : Alien::librdkafka->libs
+        ;
+        # cmake/OSX bug: -lz gets transformed into
+        #   -l/abs/path/to/libz.tbd
+        # in systems with Apple's "built-in dynamic linker cache"
+        $libs =~ s<\B-l/></>g;
+
+        my $lib_ext = $Config{lib_ext};
+        foreach my $maybe_lib ( shellwords($libs) ) {
+            if ( $maybe_lib =~ m/\B-l(\S+)/ ) {
+                # -lfoo
+                push @$makemaker_libs, $maybe_lib;
+            }
+            elsif ( $maybe_lib =~ m<-L(\S+)> ) {
+                my $lib_dir = $1;
+                # /path/to/libs
+                # add '-Wl,-rpath=$dir'
+                $libs = '-Wl,-rpath,' . $lib_dir . ' ' . $libs;
+            }
+            elsif ( $maybe_lib =~ m<^/.+$lib_ext$> ) {
+                # .a file in pkg-config --libs output -- this needs to come after the -o
+                push @archive_after, $maybe_lib;
+            }
+        }
+
+        $lddlflags .= ' ' . $libs;
+
+        1;
+    } or do {
+        my $alien_librdkafka_error = $@ || 'Zombie error';
+        die "pkg-config nor Alien::librdkafka could find kafka; bailing out!\n"
+           ."PkgConfig error: $pkg_config_error\n"
+           ."Alien::librdkafka error: $alien_librdkafka_error\n"
+        ;
+    };
+};
 
-print "Compiling Net::Kafka with librdkafka $rdkafka{modversion}\n\n";
 
 WriteMakefile(
+    INC          => $makemaker_inc,
+    LIBS         => $makemaker_libs,
+    LDDLFLAGS    => $lddlflags,
+    CCFLAGS      => $ccflags,
+    PERL_ARCHIVE_AFTER => join(' ', @archive_after),
     NAME          => 'Net::Kafka',
     DISTNAME      => 'Net-Kafka',
     AUTHOR        => [
@@ -40,7 +125,6 @@ WriteMakefile(
     LICENSE       => 'perl',
     VERSION_FROM  => 'lib/Net/Kafka.pm',
     ABSTRACT_FROM => 'lib/Net/Kafka.pm',
-    LIBS          => [ "-lrdkafka -lpthread" ],
     OBJECT        => '$(O_FILES)',
     TYPEMAPS      => ['typemap'],
     PREREQ_PM           => {
@@ -50,6 +134,14 @@ WriteMakefile(
     },
     META_MERGE    => {
         "meta-spec" => { version => 2 },
+        prereqs   => {
+            configure => {
+                # optionally use Alien::librdkafka
+                recommends => {
+                    'Alien::librdkafka' => '0.01',
+                },
+            },
+        },
         resources => {
             homepage    => 'https://github.com/bookingcom/perl-Net-Kafka',
             bugtracker  => {