From 7fb8b84143f2aa926cb3f5f2a504a4470482d24b Mon Sep 17 00:00:00 2001
From: Axel Huebl <axel.huebl@plasma.ninja>
Date: Thu, 3 Mar 2022 18:55:55 -0800
Subject: [PATCH] CMake: Optional Install if Embedded

When adding this library as embedded library with private
"target link", e.g., only used inside private source files, the
library does not need to be installed when the main project gets
installed.

This adds an additional option `toml11_INSTALL` similar to the
test-build control switch in order to skip installing headers and
CMake config files if requested.

Avoids using
```cmake
add_subdirectory(path/to/toml11 EXCLUDE_FROM_ALL)
```

which has further side-effects:
https://cmake.org/cmake/help/v3.0/command/add_subdirectory.html
---
 CMakeLists.txt | 61 ++++++++++++++++++++++++++------------------------
 1 file changed, 32 insertions(+), 29 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index babb172..3a06cf4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,6 +4,7 @@ enable_testing()
 project(toml11 VERSION 3.7.0)
 
 option(toml11_BUILD_TEST "Build toml tests" OFF)
+option(toml11_INSTALL "Install CMake targets during install step." ON)
 option(toml11_TEST_WITH_ASAN  "use LLVM address sanitizer" OFF)
 option(toml11_TEST_WITH_UBSAN "use LLVM undefined behavior sanitizer" OFF)
 
@@ -75,38 +76,40 @@ write_basic_package_version_file(
     COMPATIBILITY SameMajorVersion
 )
 
-configure_package_config_file(
-    cmake/toml11Config.cmake.in
-    ${toml11_config}
-    INSTALL_DESTINATION ${toml11_install_cmake_dir}
-    PATH_VARS toml11_install_cmake_dir
-)
+if (toml11_INSTALL)
+    configure_package_config_file(
+        cmake/toml11Config.cmake.in
+        ${toml11_config}
+        INSTALL_DESTINATION ${toml11_install_cmake_dir}
+        PATH_VARS toml11_install_cmake_dir
+    )
 
-# Install config files
-install(FILES ${toml11_config} ${toml11_config_version}
-    DESTINATION ${toml11_install_cmake_dir}
-)
+    # Install config files
+    install(FILES ${toml11_config} ${toml11_config_version}
+        DESTINATION ${toml11_install_cmake_dir}
+    )
 
-# Install header files
-install(
-    FILES toml.hpp
-    DESTINATION "${toml11_install_include_dir}"
-)
-install(
-    DIRECTORY "toml"
-    DESTINATION "${toml11_install_include_dir}"
-    FILES_MATCHING PATTERN "*.hpp"
-)
+    # Install header files
+    install(
+        FILES toml.hpp
+        DESTINATION "${toml11_install_include_dir}"
+    )
+    install(
+        DIRECTORY "toml"
+        DESTINATION "${toml11_install_include_dir}"
+        FILES_MATCHING PATTERN "*.hpp"
+    )
 
-# Export targets and install them
-install(TARGETS toml11
-    EXPORT toml11Targets
-)
-install(EXPORT toml11Targets
-    FILE toml11Targets.cmake
-    DESTINATION ${toml11_install_cmake_dir}
-    NAMESPACE toml11::
-)
+    # Export targets and install them
+    install(TARGETS toml11
+        EXPORT toml11Targets
+    )
+    install(EXPORT toml11Targets
+        FILE toml11Targets.cmake
+        DESTINATION ${toml11_install_cmake_dir}
+        NAMESPACE toml11::
+    )
+endif()
 
 if (toml11_BUILD_TEST)
     add_subdirectory(tests)