build: optionally build and install with meson

This commit adds several meson.build, which successfully build and
install Lix executables, libraries, and headers. Meson does not yet
build docs, Perl bindings, or run tests, which will be added in
following commits. As such, this commit does not remove the existing
build system, or make it the default, and also as such, this commit has
several FIXMEs and TODOs as notes for what should be done before the
existing autoconf + make buildsystem can be removed and Meson made the
default. This commit does not modify any source files.

A Meson-enabled build is also added as a Hydra job, and to
`nix flake check`.

Change-Id: I667c8685b13b7bab91e281053f807a11616ae3d4

1 files changed, 19 insertions, 1 deletions

diff --git a/flake.nix b/flake.nix
index cd5727415..5ab36408b 100644
--- a/flake.nix
+++ b/flake.nix
@@ -204,6 +204,16 @@
         # Binary package for various platforms.
         build = forAllSystems (system: self.packages.${system}.nix);
 
+        # FIXME(Qyriad): remove this when the migration to Meson has been completed.
+        mesonBuild = forAllSystems (system: self.packages.${system}.nix.override {
+          buildWithMeson = true;
+        });
+        mesonBuildClang = forAllSystems (system:
+            nixpkgsFor.${system}.stdenvs.clangStdenvPackages.nix.override {
+              buildWithMeson = true;
+            }
+        );
+
         # Perl bindings for various platforms.
         perlBindings = forAllSystems (system: nixpkgsFor.${system}.native.nix.perl-bindings);
 
@@ -262,6 +272,9 @@
       };
 
       checks = forAllSystems (system: {
+        # FIXME(Qyriad): remove this when the migration to Meson has been completed.
+        mesonBuild = self.hydraJobs.mesonBuild.${system};
+        mesonBuildClang = self.hydraJobs.mesonBuildClang.${system};
         binaryTarball = self.hydraJobs.binaryTarball.${system};
         perlBindings = self.hydraJobs.perlBindings.${system};
         nixpkgsLibTests = self.hydraJobs.tests.nixpkgsLibTests.${system};
@@ -328,7 +341,12 @@
                   # for some reason that seems accidental and was changed in
                   # NixOS 24.05-pre, clang-tools is pinned to LLVM 14 when
                   # default LLVM is newer.
-                  (pkgs.buildPackages.clang-tools.override { inherit (pkgs.buildPackages) llvmPackages; });
+                  (pkgs.buildPackages.clang-tools.override { inherit (pkgs.buildPackages) llvmPackages; })
+                ++ [
+                  # FIXME(Qyriad): remove once the migration to Meson is complete.
+                  pkgs.buildPackages.meson
+                  pkgs.buildPackages.ninja
+                ];
 
               src = null;