build: Rework path construction to reliably add prefix

There were a couple of custom paths which could end up being relative,
rather than absolute, due to not properly prefixing them with
`get_option('prefix')`.

The use of `join_paths()` here correctly drops all path components
before the final absolute path in the list of arguments. So if someone
configures GLib with an absolute path for `gio_module_dir`, that will be
used unprefixed; but if someone configures with a relative path, it will
be prefixed by `get_option('prefix)`.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Fixes: #1919

gio/gdbus-2.0/codegen/meson.build

@@ -24,7 +24,7 @@ gdbus_codegen = configure_file(input : 'gdbus-codegen.in',
   # Provide tools for others when we're a subproject and they use the Meson GNOME module
 meson.override_find_program('gdbus-codegen', gdbus_codegen)
 
-codegen_dir = join_paths(get_option('datadir'), 'glib-2.0/codegen')
+codegen_dir = join_paths(glib_datadir, 'glib-2.0', 'codegen')
 
 gdbus_codegen_built_files = []
 gdbus_codegen_built_files += configure_file(input : 'config.py.in',

gio/meson.build

@@ -811,9 +811,10 @@ libgio = library('gio-2.0',
   link_args : [noseh_link_args, glib_link_flags],
 )
 
-giomodulesdir = get_option('gio_module_dir')
-if giomodulesdir == ''
-  giomodulesdir = join_paths('${libdir}', 'gio', 'modules')
+if get_option('gio_module_dir') != ''
+  pkgconfig_giomodulesdir = join_paths('${prefix}', get_option('gio_module_dir'))
+else
+  pkgconfig_giomodulesdir = join_paths('${libdir}', 'gio', 'modules')
 endif
 
 schemas_subdir = join_paths('glib-2.0', 'schemas')
@@ -824,7 +825,7 @@ pkg.generate(libgio,
   variables : ['datadir=' + join_paths('${prefix}', get_option('datadir')),
                'schemasdir=' + join_paths('${datadir}', schemas_subdir),
                'bindir=' + join_paths('${prefix}', get_option('bindir')),
-               'giomoduledir=' + giomodulesdir,
+               'giomoduledir=' + pkgconfig_giomodulesdir,
                'gio=' + join_paths('${bindir}', 'gio'),
                'gio_querymodules=' + join_paths('${bindir}', 'gio-querymodules'),
                'glib_compile_schemas=' + join_paths('${bindir}', 'glib-compile-schemas'),

glib/gnulib/meson.build

@@ -338,6 +338,6 @@ gnulib_lib = static_library('gnulib', gnulib_sources,
   dependencies : [libm],
   include_directories : [configinc, glibinc, include_directories ('.')],
   pic : true,
-  c_args : ['-DGCC_LINT=1', '-DLIBDIR="@0@"'.format(get_option('libdir')), '-DGLIB_COMPILATION', '-DG_LOG_DOMAIN="GLib"' ] + glib_hidden_visibility_args + extra_gnulib_args)
+  c_args : ['-DGCC_LINT=1', '-DLIBDIR="@0@"'.format(glib_libdir), '-DGLIB_COMPILATION', '-DG_LOG_DOMAIN="GLib"' ] + glib_hidden_visibility_args + extra_gnulib_args)
 
 gnulib_libm_dependency = [libm]

glib/libcharset/meson.build

@@ -1,9 +1,4 @@
-charsetalias_dir = get_option('charsetalias_dir')
-if charsetalias_dir == ''
-  charsetalias_dir = get_option('libdir')
-endif
-
 charset_lib = static_library('charset', 'localcharset.c',
   include_directories : configinc,
   pic : true,
-  c_args : [ '-DGLIB_CHARSETALIAS_DIR="@0@"'.format(charsetalias_dir) ] + glib_hidden_visibility_args)
+  c_args : [ '-DGLIB_CHARSETALIAS_DIR="@0@"'.format(glib_charsetaliasdir) ] + glib_hidden_visibility_args)

meson.build

@@ -63,13 +63,20 @@ glib_libexecdir = join_paths(glib_prefix, get_option('libexecdir'))
 glib_datadir = join_paths(glib_prefix, get_option('datadir'))
 glib_pkgdatadir = join_paths(glib_datadir, 'glib-2.0')
 glib_includedir = join_paths(glib_prefix, get_option('includedir'))
-glib_giomodulesdir = get_option('gio_module_dir')
-if glib_giomodulesdir == ''
+if get_option('gio_module_dir') != ''
+  glib_giomodulesdir = join_paths(glib_prefix, get_option('gio_module_dir'))
+else
   glib_giomodulesdir = join_paths(glib_libdir, 'gio', 'modules')
 endif
 
 glib_pkgconfigreldir = join_paths(glib_libdir, 'pkgconfig')
 
+if get_option('charsetalias_dir') != ''
+  glib_charsetaliasdir = join_paths(glib_prefix, get_option('charsetalias_dir'))
+else
+  glib_charsetaliasdir = glib_libdir
+endif
+
 installed_tests_metadir = join_paths(glib_datadir, 'installed-tests', meson.project_name())
 installed_tests_execdir = join_paths(glib_libexecdir, 'installed-tests', meson.project_name())
 installed_tests_enabled = get_option('installed_tests')
@@ -2216,7 +2223,7 @@ if get_option('man')
     'http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl',
     '@INPUT@',
   ]
-  man1_dir = get_option('mandir') + '/man1'
+  man1_dir = join_paths(glib_prefix, get_option('mandir'), 'man1')
 endif
 
 gnome = import('gnome')