build: Refactor CMake back to in-tree CMakeLists

This moves the build definitions back to src/ subdirectories
(CMakeLists.txt per component). Configuration and dependencies are
kept out of tree. Configuration options are bundled into cmake/config/
modules. Dependencies are grouped by component (system/, crypt/, eth/,
coverage/, etc.). It now consistently uses target-based commands
(target_include_directories, target_link_libraries) instead of global
include_directories(). Proper PRIVATE/PUBLIC visibility for executable
link libraries. CONFIG_OUROBOROS_DEBUG now properly set based on being
a valid debug config (not just checking the string name).

It also adds OuroborosTargets export for find_package() support and
CMake package config files (OuroborosConfig.cmake) for easier
integration with CMake projects.

The build logic now follows more idiomatic CMake practices with
configuration separated from target definitions.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 35 insertions, 19 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2ed52fd2..d225d29d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,4 @@
-cmake_minimum_required(VERSION 2.8.12.2...4.0.3.0)
-cmake_policy(VERSION ${CMAKE_VERSION})
+cmake_minimum_required(VERSION 3.19)
 
 set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
 
@@ -7,50 +6,67 @@ project(ouroboros C)
 
 include(GNUInstallDirs)
 
+include(utils/DebugTargets)
+
 include(version)
 include(package)
 
 include(compiler)
 
-if (CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
-  if (APPLE)
+if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
+  if(APPLE)
     set(CMAKE_INSTALL_PREFIX "/usr/local" CACHE STRING
       "Installation Prefix" FORCE)
   else()
     set(CMAKE_INSTALL_PREFIX "/usr" CACHE STRING
       "Installation Prefix" FORCE)
   endif()
-endif ()
+endif()
 
-if (APPLE)
+if(APPLE)
   set(CMAKE_MACOSX_RPATH 1)
-  include_directories("/usr/local/include/")
+  # Homebrew installs to /usr/local/include on Intel, /opt/homebrew/include on ARM
+  set(APPLE_INCLUDE_DIRS "/usr/local/include" "/opt/homebrew/include"
+      CACHE INTERNAL "Apple system include directories")
 endif()
 
-if (CMAKE_INSTALL_PREFIX STREQUAL "/usr")
+if(CMAKE_INSTALL_PREFIX STREQUAL "/usr")
   set(RPATH_PREFIX "")
-else ()
+else()
   set(RPATH_PREFIX ${CMAKE_INSTALL_PREFIX})
-endif ()
+endif()
 
 set(CMAKE_SKIP_BUILD_RPATH FALSE)
 set(CMAKE_BUILD_WITH_INSTALL_RPATH FALSE)
 set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
 
 list(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES
-  "${RPATH_PREFIX}/lib" isSystemDir)
-IF ("${isSystemDir}" STREQUAL "-1")
-  set(CMAKE_INSTALL_RPATH "${RPATH_PREFIX}/lib")
-ENDIF ("${isSystemDir}" STREQUAL "-1")
+  "${RPATH_PREFIX}/${CMAKE_INSTALL_LIBDIR}" isSystemDir)
+if(isSystemDir STREQUAL "-1")
+  set(CMAKE_INSTALL_RPATH "${RPATH_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+endif()
 
 include(dependencies)
 
-include(include)
-include(lib)
-include(ipcp)
-include(irmd)
-include(tools)
+# Configuration options (must be loaded before component modules)
+include(config/global)
+include(config/lib)
+include(config/ssm)
+include(config/irmd)
+include(config/ipcp/common)
+include(config/ipcp/unicast)
+include(config/ipcp/broadcast)
+include(config/ipcp/local)
+include(config/ipcp/eth)
+include(config/ipcp/udp)
+
 include(tests)
+include(include)
+add_subdirectory(src/lib)
+add_subdirectory(src/irmd)
+add_subdirectory(src/ipcpd)
+add_subdirectory(src/tools)
+setup_coverage_target()
 include(doc)
 
 include(install)