Merge changes Ic4be41eb,I48db2385 into main

* changes:
  devshells: only enable pch for clang
  build: expose option to enable or disable precompiled std headers

meson.build

@@ -129,6 +129,20 @@ endif
 
 cxx = meson.get_compiler('cpp')
 
+
+# clangd breaks when GCC is using precompiled headers lmao
+# https://git.lix.systems/lix-project/lix/issues/374
+should_pch = get_option('enable-pch-std')
+summary('PCH C++ stdlib', should_pch, bool_yn : true)
+if should_pch
+  # Unlike basically everything else that takes a file, Meson requires the arguments to
+  # cpp_pch : to be strings and doesn't accept files(). So absolute path it is.
+  cpp_pch = [meson.project_source_root() / 'src/pch/precompiled-headers.hh']
+else
+  cpp_pch = []
+endif
+
+
 # Translate some historical and Mesony CPU names to Lixy CPU names.
 # FIXME(Qyriad): the 32-bit x86 code is not tested right now, because cross compilation for Lix
 # to those architectures is currently broken for other reasons, namely:

meson.options

@@ -64,3 +64,7 @@ option('internal-api-docs', type : 'feature', value : 'auto',
 option('profile-dir', type : 'string', value : 'etc/profile.d',
   description : 'the path to install shell profile files',
 )
+
+option('enable-pch-std', type : 'boolean', value : true,
+  description : 'whether to use precompiled headers for C++\'s standard library (breaks clangd if you\'re using GCC)',
+)

package.nix

@@ -436,9 +436,14 @@ stdenv.mkDerivation (finalAttrs: {
           # For Meson to find Boost.
           env = finalAttrs.env;
 
+          mesonFlags =
             # I guess this is necessary because mesonFlags to mkDerivation doesn't propagate in inputsFrom,
             # which only propagates stuff set in hooks? idk.
-          inherit (finalAttrs) mesonFlags;
+            finalAttrs.mesonFlags
+            # Clangd breaks when GCC is using precompiled headers, so for the devshell specifically
+            # we make precompiled C++ stdlib conditional on using Clang.
+            # https://git.lix.systems/lix-project/lix/issues/374
+            ++ [ (lib.mesonBool "enable-pch-std" stdenv.cc.isClang) ];
 
           packages =
             lib.optional (stdenv.cc.isClang && hostPlatform == buildPlatform) clang-tools_llvm

src/libcmd/meson.build

@@ -54,7 +54,7 @@ libcmd = library(
     nlohmann_json,
     lix_doc
   ],
-  cpp_pch : ['../pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
   install : true,
   # FIXME(Qyriad): is this right?
   install_rpath : libdir,

src/libexpr/meson.build

@@ -145,7 +145,7 @@ libexpr = library(
   include_directories : [
     '../libmain',
   ],
-  cpp_pch : ['../pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
   install : true,
   # FIXME(Qyriad): is this right?
   install_rpath : libdir,

src/libfetchers/meson.build

@@ -30,7 +30,7 @@ libfetchers = library(
     liblixutil,
     nlohmann_json,
   ],
-  cpp_pch : ['../pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
   install : true,
   # FIXME(Qyriad): is this right?
   install_rpath : libdir,

src/libmain/meson.build

@@ -20,7 +20,7 @@ libmain = library(
     liblixutil,
     liblixstore,
   ],
-  cpp_pch : ['../pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
   install : true,
   # FIXME(Qyriad): is this right?
   install_rpath : libdir,

src/libstore/meson.build

@@ -220,7 +220,7 @@ libstore = library(
     nlohmann_json,
   ],
   cpp_args : cpp_args,
-  cpp_pch : ['../pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
   install : true,
   # FIXME(Qyriad): is this right?
   install_rpath : libdir,

src/libutil/meson.build

@@ -129,7 +129,7 @@ libutil = library(
     openssl,
     nlohmann_json,
   ],
-  cpp_pch : ['../pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
   implicit_include_directories : true,
   install : true,
 )

src/nix/meson.build

@@ -89,7 +89,7 @@ nix = executable(
     boehm,
     nlohmann_json,
   ],
-  cpp_pch : ['../pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
   install : true,
   # FIXME(Qyriad): is this right?
   install_rpath : libdir,

tests/unit/meson.build

@@ -68,7 +68,7 @@ libutil_tester = executable(
     liblixutil_test_support,
     nlohmann_json,
   ],
-  cpp_pch : ['../../src/pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
 )
 
 test(
@@ -103,7 +103,7 @@ libstore_test_support = library(
   include_directories : include_directories(
     'libstore-support',
   ),
-  cpp_pch : ['../../src/pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
 )
 liblixstore_test_support = declare_dependency(
   include_directories : include_directories('libstore-support'),
@@ -137,7 +137,7 @@ libstore_tester = executable(
     gtest,
     nlohmann_json,
   ],
-  cpp_pch : ['../../src/pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
 )
 
 test(
@@ -169,7 +169,7 @@ libexpr_test_support = library(
   include_directories : include_directories(
     'libexpr-support',
   ),
-  cpp_pch : ['../../src/pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
 )
 liblixexpr_test_support = declare_dependency(
   include_directories : include_directories('libexpr-support'),
@@ -203,7 +203,7 @@ libexpr_tester = executable(
     gtest,
     nlohmann_json,
   ],
-  cpp_pch : ['../../src/pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
 )
 
 test(
@@ -230,7 +230,7 @@ libcmd_tester = executable(
     gtest,
     boost,
   ],
-  cpp_pch : ['../../src/pch/precompiled-headers.hh'],
+  cpp_pch : cpp_pch,
 )
 
 test(