external-project: Setup devenv to run programs

docs/markdown/External-Project-module.md

@@ -5,6 +5,8 @@
 
 *This is an experimental module, API could change.*
 
+*Added 0.56.0*
+
 This module allows building code that uses build systems other than
 Meson. This module is intended to be used to build Autotools
 subprojects as fallback if the dependency couldn't be found on the
@@ -47,7 +49,8 @@ Known limitations:
   from `-uninstalled.pc` files. This is arguably a bug that could be fixed in
   future version of pkg-config/pkgconf.
 
-*Added 0.56.0*
+*Since 1.7.0* [Meson devenv][Commands.md#devenv] setup `PATH` and
+`LD_LIBRARY_PATH` to be able to run programs.
 
 ## Functions
 
@@ -78,7 +81,8 @@ Keyword arguments:
   added in case some tags are not found in `configure_options`:
   `'--prefix=@PREFIX@'`, `'--libdir=@PREFIX@/@LIBDIR@'`, and
   `'--includedir=@PREFIX@/@INCLUDEDIR@'`. It was previously considered a fatal
-  error to not specify them.
+  error to not specify them. *Since 1.7.0* `@BINDIR@` and `'--bindir=@PREFIX@/@BINDIR@'`
+  default argument have been added.
 - `cross_configure_options`: Extra options appended to `configure_options` only
   when cross compiling. special tag `@HOST@` will be replaced by
   `'{}-{}-{}'.format(host_machine.cpu_family(), build_machine.system(), host_machine.system()`.

docs/markdown/snippets/external_project_devenv.md

@@ -0,0 +1,7 @@
+## Devenv support in external project module
+
+The [external project module](External-Project-module.md) now setups `PATH` and
+`LD_LIBRARY_PATH` to be able to run programs.
+
+`@BINDIR@` is now substitued in arguments and `'--bindir=@PREFIX@/@BINDIR@'`
+default argument have been added.

mesonbuild/modules/external_project.py

@@ -81,6 +81,9 @@ def __init__(self,
         _l = self.env.coredata.get_option(OptionKey('libdir'))
         assert isinstance(_l, str), 'for mypy'
         self.libdir = Path(_l)
+        _l = self.env.coredata.get_option(OptionKey('bindir'))
+        assert isinstance(_l, str), 'for mypy'
+        self.bindir = Path(_l)
         _i = self.env.coredata.get_option(OptionKey('includedir'))
         assert isinstance(_i, str), 'for mypy'
         self.includedir = Path(_i)
@@ -118,6 +121,7 @@ def _configure(self, state: 'ModuleState') -> None:
 
         d = [('PREFIX', '--prefix=@PREFIX@', self.prefix.as_posix()),
              ('LIBDIR', '--libdir=@PREFIX@/@LIBDIR@', self.libdir.as_posix()),
+             ('BINDIR', '--bindir=@PREFIX@/@BINDIR@', self.bindir.as_posix()),
              ('INCLUDEDIR', None, self.includedir.as_posix()),
              ]
         self._validate_configure_options(d, state)
@@ -278,6 +282,7 @@ class ExternalProjectModule(ExtensionModule):
 
     def __init__(self, interpreter: 'Interpreter'):
         super().__init__(interpreter)
+        self.devenv: T.Optional[EnvironmentVariables] = None
         self.methods.update({'add_project': self.add_project,
                              })
 
@@ -299,8 +304,19 @@ def add_project(self, state: 'ModuleState', args: T.Tuple[str], kwargs: 'AddProj
                                   kwargs['env'],
                                   kwargs['verbose'],
                                   kwargs['depends'])
+        abs_libdir = Path(project.install_dir, project.rel_prefix, project.libdir).as_posix()
+        abs_bindir = Path(project.install_dir, project.rel_prefix, project.bindir).as_posix()
+        env = state.environment.get_env_for_paths({abs_libdir}, {abs_bindir})
+        if self.devenv is None:
+            self.devenv = env
+        else:
+            self.devenv.merge(env)
         return ModuleReturnValue(project, project.targets)
 
+    def postconf_hook(self, b: build.Build) -> None:
+        if self.devenv is not None:
+            b.devenv.append(self.devenv)
+
 
 def initialize(interp: 'Interpreter') -> ExternalProjectModule:
     return ExternalProjectModule(interp)