meson: allow customize perl installation path

Some distros, notably Fedora, want to install non-core Perl libraries
into specific directory, namely /usr/share/perl5/vendor_perl.

The Makefile build system allows this by overriding perllibdir variable,
let's make meson works on par with our Makefile.

Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

perl/FromCPAN/Mail/meson.build

@@ -3,6 +3,6 @@ test_dependencies += custom_target(
   output: 'Address.pm',
   command: generate_perl_command,
   install: true,
-  install_dir: get_option('datadir') / 'perl5/FromCPAN/Mail',
+  install_dir: perllibdir / 'FromCPAN/Mail',
   depends: [git_version_file],
 )

perl/FromCPAN/meson.build

@@ -3,7 +3,7 @@ test_dependencies += custom_target(
   output: 'Error.pm',
   command: generate_perl_command,
   install: true,
-  install_dir: get_option('datadir') / 'perl5/FromCPAN',
+  install_dir: perllibdir / 'FromCPAN',
   depends: [git_version_file],
 )
 

perl/Git/LoadCPAN/Mail/meson.build

@@ -3,6 +3,6 @@ test_dependencies += custom_target(
   output: 'Address.pm',
   command: generate_perl_command,
   install: true,
-  install_dir: get_option('datadir') / 'perl5/Git/LoadCPAN/Mail',
+  install_dir: perllibdir / 'Git/LoadCPAN/Mail',
   depends: [git_version_file],
 )

perl/Git/LoadCPAN/meson.build

@@ -3,7 +3,7 @@ test_dependencies += custom_target(
   output: 'Error.pm',
   command: generate_perl_command,
   install: true,
-  install_dir: get_option('datadir') / 'perl5/Git/LoadCPAN',
+  install_dir: perllibdir / 'Git/LoadCPAN',
   depends: [git_version_file],
 )
 

perl/Git/SVN/Memoize/meson.build

@@ -3,6 +3,6 @@ test_dependencies += custom_target(
   output: 'YAML.pm',
   command: generate_perl_command,
   install: true,
-  install_dir: get_option('datadir') / 'perl5/Git/SVN',
+  install_dir: perllibdir / 'Git/SVN',
   depends: [git_version_file],
 )

perl/Git/SVN/meson.build

@@ -13,7 +13,7 @@ foreach source : [
     output: source,
     command: generate_perl_command,
     install: true,
-    install_dir: get_option('datadir') / 'perl5/Git/SVN',
+    install_dir: perllibdir / 'Git/SVN',
     depends: [git_version_file],
   )
 endforeach

perl/Git/meson.build

@@ -10,7 +10,7 @@ foreach source : [
     output: source,
     command: generate_perl_command,
     install: true,
-    install_dir: get_option('datadir') / 'perl5/Git',
+    install_dir: perllibdir / 'Git',
     depends: [git_version_file],
   )
 endforeach

perl/meson.build

@@ -3,7 +3,7 @@ test_dependencies += custom_target(
   output: 'Git.pm',
   command: generate_perl_command,
   install: true,
-  install_dir: get_option('datadir') / 'perl5',
+  install_dir: perllibdir,
   depends: [git_version_file],
 )