meson_options.txt: add host-gi, gi-cross-wrapper, gi-ldd-wrapper, introspection-data and pkgconfig-sysroot-path options

With the first option, gobject-introspection tools (g-ir-doc-tool and g-ir-scanner)
that are already installed in the host system will be used for building the source tree.

With the second option, g-ir-scanner will be instructed to use an executable
wrapper to run binaries it's producing, and g-ir-compiler will be run
through the same wrapper (host system's g-ir-compiler cannot be used because
it's producing architecture-specific output).

With the third option, giscanner will be instructed to use a special ldd
command instead of system's ldd (which does not work when the binary to inspect
is compiled for a different architecture).

With the fourth option, it is possible to disable building of introspection data
(.gir and .typelib files), which may be difficult or impossible in cross-compilation
environments, because of lack of emulation (or native hardware) for the target architecture
on which the target binaries can be run.

With the fifth option, paths returned by pkg-config are prefixed with the sysroot
path (which is the destination path for cross-compiled items on the system where
cross-compilation happens).

These options are useful when cross-compiling for a different target architecture.

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>

3 files changed, 68 insertions, 18 deletions

diff --git a/gir/meson.build b/gir/meson.build
index c312100c..a0280330 100644
--- a/gir/meson.build
+++ b/gir/meson.build
@@ -41,16 +41,29 @@ gir_files = [
 typelibdir = join_paths(get_option('libdir'), 'girepository-1.0')
 install_data(gir_files, install_dir: girdir)
 
-scanner_command = [
-  python,
-  girscanner,
-  '--output=@OUTPUT@',
-  '--no-libtool',
-  '--quiet',
-  '--reparse-validate',
-  '--add-include-path', join_paths(meson.current_build_dir()),
-  '--add-include-path', join_paths(meson.current_source_dir()),
-]
+if get_option('enable-host-gi')
+    scanner_command = [
+      'g-ir-scanner',
+      '--output=@OUTPUT@',
+      '--no-libtool',
+      '--quiet',
+      '--reparse-validate',
+      '--add-include-path', join_paths(meson.current_build_dir()),
+      '--add-include-path', join_paths(meson.current_source_dir()),
+    ]
+else
+    scanner_command = [
+      python,
+      girscanner,
+      '--output=@OUTPUT@',
+      '--no-libtool',
+      '--quiet',
+      '--reparse-validate',
+      '--add-include-path', join_paths(meson.current_build_dir()),
+      '--add-include-path', join_paths(meson.current_source_dir()),
+    ]
+endif
+
 
 dep_type = glib_dep.type_name()
 if dep_type == 'internal'
@@ -63,6 +76,12 @@ if dep_type == 'internal'
                       '--extra-library=glib-2.0', '--extra-library=gobject-2.0']
 endif
 
+if get_option('enable-gi-cross-wrapper') != ''
+  scanner_command += ['--use-binary-wrapper=' + get_option('enable-gi-cross-wrapper')]
+endif
+if get_option('enable-gi-ldd-wrapper') != ''
+  scanner_command += ['--use-ldd-wrapper=' + get_option('enable-gi-ldd-wrapper')]
+endif
 # Take a glob and print to newlines
 globber = '''
 from glob import glob
@@ -89,8 +108,8 @@ glib_command = scanner_command + [
 
 if dep_type == 'pkgconfig'
   glib_command += ['--external-library', '--pkg=glib-2.0']
-  glib_libdir = glib_dep.get_pkgconfig_variable('libdir')
-  glib_incdir = join_paths(glib_dep.get_pkgconfig_variable('includedir'), 'glib-2.0')
+  glib_libdir = get_option('pkgconfig-sysroot-path') + glib_dep.get_pkgconfig_variable('libdir')
+  glib_incdir = get_option('pkgconfig-sysroot-path') + join_paths(glib_dep.get_pkgconfig_variable('includedir'), 'glib-2.0')
   glib_libincdir = join_paths(glib_libdir, 'glib-2.0', 'include')
   glib_files += join_paths(glib_incdir, 'gobject', 'glib-types.h')
   glib_files += join_paths(glib_libincdir, 'glibconfig.h')
@@ -345,7 +364,7 @@ if giounix_dep.found()
   dep_type = giounix_dep.type_name()
   if dep_type == 'pkgconfig'
     gio_command += ['--pkg=gio-unix-2.0']
-    giounix_includedir = join_paths(giounix_dep.get_pkgconfig_variable('includedir'), 'gio-unix-2.0')
+    giounix_includedir = get_option('pkgconfig-sysroot-path') + join_paths(giounix_dep.get_pkgconfig_variable('includedir'), 'gio-unix-2.0')
     # Get the installed gio-unix header list
     ret = run_command(python, '-c', globber.format(join_paths(giounix_includedir, 'gio', '*.h')))
     if ret.returncode() != 0
@@ -428,15 +447,24 @@ gir_files += custom_target('gir-girepository',
 )
 
 typelibs = []
+if get_option('enable-gi-cross-wrapper') != ''
+    gircompiler_command = [get_option('enable-gi-cross-wrapper'), gircompiler.full_path(), '-o', '@OUTPUT@', '@INPUT@',
+              '--includedir', meson.current_build_dir(),
+              '--includedir', meson.current_source_dir(),
+    ]
+else
+    gircompiler_command = [gircompiler, '-o', '@OUTPUT@', '@INPUT@',
+              '--includedir', meson.current_build_dir(),
+              '--includedir', meson.current_source_dir(),
+    ]
+endif
+
 foreach gir : gir_files
   typelibs += custom_target('generate-typelib-@0@'.format(gir).underscorify(),
     input: gir,
     output: '@BASENAME@.typelib',
     depends: [gobject_gir, ],
-    command: [gircompiler, '-o', '@OUTPUT@', '@INPUT@',
-              '--includedir', meson.current_build_dir(),
-              '--includedir', meson.current_source_dir(),
-    ],
+    command: gircompiler_command,
     install: true,
     install_dir: typelibdir,
   )
diff --git a/meson.build b/meson.build
index df18e467..f8f52d14 100644
--- a/meson.build
+++ b/meson.build
@@ -196,7 +196,9 @@ endif
 subdir('girepository')
 subdir('tools')
 subdir('giscanner')
-subdir('gir')
+if get_option('enable-introspection-data') == true
+    subdir('gir')
+endif
 subdir('docs')
 subdir('tests')
 
diff --git a/meson_options.txt b/meson_options.txt
index 7bed278d..98491032 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -25,3 +25,23 @@ option('python', type: 'string', value: 'python3',
 option('gir_dir_prefix', type: 'string',
   description: 'Intermediate prefix for gir installation under ${prefix}'
 )
+
+option('enable-host-gi', type: 'boolean', value : false,
+  description: 'Use gobject introspection tools installed in the host system (useful when cross-compiling)'
+)
+
+option('enable-gi-cross-wrapper', type: 'string',
+  description: 'Use a wrapper to run gicompiler and binaries produced by giscanner (useful when cross-compiling)'
+)
+
+option('enable-gi-ldd-wrapper', type: 'string',
+  description: 'Use a ldd wrapper instead of system ldd command in giscanner (useful when cross-compiling)'
+)
+
+option('enable-introspection-data', type: 'boolean', value : true,
+  description: 'Build introspection data (.gir and .typelib files) in addition to library and tools'
+)
+
+option('pkgconfig-sysroot-path', type: 'string',
+  description: 'Specify a sysroot path to prepend to pkgconfig output (useful when cross-compiling)'
+)