From 8ceacbac6b6b0f95256baa1c250ac6111c0bb887 Mon Sep 17 00:00:00 2001
From: Rudi Heitbaum <rudi@heitbaum.com>
Date: Fri, 25 Apr 2025 07:18:31 +0000
Subject: [PATCH] build: define CMAKE_EXPORT_COMPILE_COMMANDS as an environment
 variable not a define.

When building utfcpp (and other packages) a CMake warning is issued.

    CMake Warning:
      Manually-specified variables were not used by the project:

        CMAKE_EXPORT_COMPILE_COMMANDS

Before this change the following files are present:

    $ cd build.LibreELEC-Generic.x86_64-13.0-devel/build

    $ find utfcpp-4.0.6 -name build.ninja
    utfcpp-4.0.6/.x86_64-libreelec-linux-gnu/build.ninja
    $ find utfcpp-4.0.6 -name compile_commands.json

    $ find soxr-0.1.3 -name build.ninja
    soxr-0.1.3/.x86_64-libreelec-linux-gnu/build.ninja
    $ find soxr-0.1.3 -name compile_commands.json
    soxr-0.1.3/.x86_64-libreelec-linux-gnu/compile_commands.json

When removing the define CMAKE_EXPORT_COMPILE_COMMANDS:

--- a/scripts/build
+++ b/scripts/build
@@ -147,8 +147,7 @@
   MESON_BUILD_TYPE="plain"
 fi

-CMAKE_GENERATOR_NINJA="-GNinja \
-                       -DCMAKE_EXPORT_COMPILE_COMMANDS=ON"
+CMAKE_GENERATOR_NINJA="-GNinja"

 # configure TARGET build defaults
 TARGET_CONFIGURE_OPTS="--host=${TARGET_NAME} \

The resulting build do not have the warning with utfcpp but the files
compile_commands.json are not created (as expected.)

    $ find utfcpp-4.0.6 -name build.ninja
    utfcpp-4.0.6/.x86_64-libreelec-linux-gnu/build.ninja
    $ find utfcpp-4.0.6 -name compile_commands.json

    $ find soxr-0.1.3 -name build.ninja
    soxr-0.1.3/.x86_64-libreelec-linux-gnu/build.ninja
    $ find soxr-0.1.3 -name compile_commands.json

With the change to declare CMAKE_EXPORT_COMPILE_COMMANDS as an environment
variable the warning is not preset with utfcpp and the compile_commands.json
are created, matching the current functionaility but without the warning.

Ref:
- https://cmake.org/cmake/help/latest/variable/CMAKE_EXPORT_COMPILE_COMMANDS.html
  - This is initialized by the CMAKE_EXPORT_COMPILE_COMMANDS environment variable.
- https://cmake.org/cmake/help/latest/envvar/CMAKE_EXPORT_COMPILE_COMMANDS.html#envvar:CMAKE_EXPORT_COMPILE_COMMANDS
- https://stackoverflow.com/questions/20059670/how-to-use-cmake-export-compile-commands
---
 scripts/build | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/scripts/build b/scripts/build
index fa170e1bcc..d53436d9fe 100755
--- a/scripts/build
+++ b/scripts/build
@@ -147,8 +147,7 @@ else
   MESON_BUILD_TYPE="plain"
 fi
 
-CMAKE_GENERATOR_NINJA="-GNinja \
-                       -DCMAKE_EXPORT_COMPILE_COMMANDS=ON"
+CMAKE_GENERATOR_NINJA="-GNinja"
 
 # configure TARGET build defaults
 TARGET_CONFIGURE_OPTS="--host=${TARGET_NAME} \
@@ -319,19 +318,19 @@ else
     # cmake builds with ninja
     "cmake:target")
       echo "Executing (target): cmake ${CMAKE_GENERATOR_NINJA} ${TARGET_CMAKE_OPTS} ${PKG_CMAKE_OPTS_TARGET} ${PKG_CMAKE_SCRIPT%/*}" | tr -s " "
-      cmake ${CMAKE_GENERATOR_NINJA} ${TARGET_CMAKE_OPTS} ${PKG_CMAKE_OPTS_TARGET} ${PKG_CMAKE_SCRIPT%/*}
+      CMAKE_EXPORT_COMPILE_COMMANDS=1 cmake ${CMAKE_GENERATOR_NINJA} ${TARGET_CMAKE_OPTS} ${PKG_CMAKE_OPTS_TARGET} ${PKG_CMAKE_SCRIPT%/*}
       ;;
     "cmake:host")
       echo "Executing (host): cmake ${CMAKE_GENERATOR_NINJA} ${HOST_CMAKE_OPTS} ${PKG_CMAKE_OPTS_HOST} ${PKG_CMAKE_SCRIPT%/*}" | tr -s " "
-      cmake ${CMAKE_GENERATOR_NINJA} ${HOST_CMAKE_OPTS} ${PKG_CMAKE_OPTS_HOST} ${PKG_CMAKE_SCRIPT%/*}
+      CMAKE_EXPORT_COMPILE_COMMANDS=1 cmake ${CMAKE_GENERATOR_NINJA} ${HOST_CMAKE_OPTS} ${PKG_CMAKE_OPTS_HOST} ${PKG_CMAKE_SCRIPT%/*}
       ;;
     "cmake:init")
       echo "Executing (init): cmake ${CMAKE_GENERATOR_NINJA} ${INIT_CMAKE_OPTS} ${PKG_CMAKE_OPTS_INIT} ${PKG_CMAKE_SCRIPT%/*}" | tr -s " "
-      cmake ${CMAKE_GENERATOR_NINJA} ${INIT_CMAKE_OPTS} ${PKG_CMAKE_OPTS_INIT} ${PKG_CMAKE_SCRIPT%/*}
+      CMAKE_EXPORT_COMPILE_COMMANDS=1 cmake ${CMAKE_GENERATOR_NINJA} ${INIT_CMAKE_OPTS} ${PKG_CMAKE_OPTS_INIT} ${PKG_CMAKE_SCRIPT%/*}
       ;;
     "cmake:bootstrap")
       echo "Executing (bootstrap): cmake ${CMAKE_GENERATOR_NINJA} ${BOOTSTRAP_CMAKE_OPTS} ${PKG_CMAKE_OPTS_BOOTSTRAP} ${PKG_CMAKE_SCRIPT%/*}" | tr -s " "
-      cmake ${CMAKE_GENERATOR_NINJA} ${BOOTSTRAP_CMAKE_OPTS} ${PKG_CMAKE_OPTS_BOOTSTRAP} ${PKG_CMAKE_SCRIPT%/*}
+      CMAKE_EXPORT_COMPILE_COMMANDS=1 cmake ${CMAKE_GENERATOR_NINJA} ${BOOTSTRAP_CMAKE_OPTS} ${PKG_CMAKE_OPTS_BOOTSTRAP} ${PKG_CMAKE_SCRIPT%/*}
       ;;
 
     # cmake builds with make