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>

meson.build

@@ -1871,14 +1871,19 @@ if perl_features_enabled
     perl_header_template = 'perl/header_templates/runtime_prefix.template.pl'
   endif
 
+  perllibdir = get_option('perllibdir')
+  if perllibdir == ''
+    perllibdir = get_option('datadir') / 'perl5'
+  endif
+
   perl_header = configure_file(
     input: perl_header_template,
     output: 'GIT-PERL-HEADER',
     configuration: {
       'GITEXECDIR_REL': get_option('libexecdir') / 'git-core',
-      'PERLLIBDIR_REL': get_option('datadir') / 'perl5',
+      'PERLLIBDIR_REL': perllibdir,
       'LOCALEDIR_REL': get_option('datadir') / 'locale',
-      'INSTLIBDIR': get_option('datadir') / 'perl5',
+      'INSTLIBDIR': perllibdir,
       'PATHSEP': pathsep,
     },
   )

meson_options.txt

@@ -1,3 +1,7 @@
+# Configuration for Git installation
+option('perllibdir', type: 'string', value: '',
+  description: 'Directory to install perl lib to. Defaults to <datadir>/perl5')
+
 # Configuration for how Git behaves at runtime.
 option('default_pager', type: 'string', value: 'less',
   description: 'Fall-back pager.')

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],
 )