Bug#1060838: meson: should use the host gobject-introspection-1.0.pc for looking up g-ir-scanner

[Helmut Grohne <helmut@subdivi.de>]

Package: meson
Version: 1.3.1-1
Severity: important
Tags: patch upstream
X-Debbugs-Cc: debian-cross@lists.debian.org, smcv@debian.org
User: debian-cross@lists.debian.org
Usertags: ftcbfs
Control: affects -1 + src:harfbuzz

Hi,

Simon worked a lot on making gobject-introspection workable with cross
compilation and this work has hit unstable now. While this seems to work
fine with autotools, it tends to fail with meson.

Among other things, Simon introduced new programs
/usr/bin/<triplet>-g-ir-scanner. When cross building, these should be
used and they'll automatically employ qemu-user when needed. He also
updated gobject-introspection-1.0.pc to have g_ir_scanner point at this
rather than plain /usr/bin/g-ir-scanner. Unfortunately, meson looks up
the gobject-introspection-1.0 dependency with native set to true. Hence,
it does not pick up the host triplet but the build triplet here and that
doesn't go well. We need to change the native argument to false here.

I'm attaching a patch demonstrating the change and it makes building
e.g. harfbuzz work. I expect this change to fix many packages hence
raising the severity to important. I'm not sure whether this is the
desired way to extend meson nor whether this has consequences for
downstreams other than Debian. How can we take care of these matters?

Helmut

--- meson-1.3.1.orig/mesonbuild/modules/__init__.py
+++ meson-1.3.1/mesonbuild/modules/__init__.py
@@ -96,7 +96,7 @@
                                                    wanted=wanted, silent=silent, for_machine=for_machine)
 
     def find_tool(self, name: str, depname: str, varname: str, required: bool = True,
-                  wanted: T.Optional[str] = None) -> T.Union['build.Executable', ExternalProgram, 'OverrideProgram']:
+                  wanted: T.Optional[str] = None, native: bool = True) -> T.Union['build.Executable', ExternalProgram, 'OverrideProgram']:
         # Look in overrides in case it's built as subproject
         progobj = self._interpreter.program_from_overrides([name], [])
         if progobj is not None:
@@ -108,7 +108,7 @@
             return ExternalProgram.from_entry(name, prog_list)
 
         # Check if pkgconfig has a variable
-        dep = self.dependency(depname, native=True, required=False, wanted=wanted)
+        dep = self.dependency(depname, native=native, required=False, wanted=wanted)
         if dep.found() and dep.type_name == 'pkgconfig':
             value = dep.get_variable(pkgconfig=varname)
             if value:
--- meson-1.3.1.orig/mesonbuild/modules/gnome.py
+++ meson-1.3.1/mesonbuild/modules/gnome.py
@@ -328,7 +328,7 @@
         }
         depname = tool_map[tool]
         varname = tool.replace('-', '_')
-        return state.find_tool(tool, depname, varname)
+        return state.find_tool(tool, depname, varname, native=depname != "gobject-introspection-1.0")
 
     @typed_kwargs(
         'gnome.post_install',