build: Refactor CMake back to in-tree CMakeListsbe

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>

6 files changed, 110 insertions, 0 deletions

diff --git a/cmake/dependencies/system/explicit_bzero.cmake b/cmake/dependencies/system/explicit_bzero.cmake
new file mode 100644
index 00000000..89ab3abc
--- /dev/null
+++ b/cmake/dependencies/system/explicit_bzero.cmake
@@ -0,0 +1,4 @@
+# Check for explicit_bzero in string.h
+# glibc requires _DEFAULT_SOURCE to expose it; harmless on other platforms
+list(APPEND CMAKE_REQUIRED_DEFINITIONS -D_DEFAULT_SOURCE)
+check_symbol_exists(explicit_bzero "string.h" HAVE_EXPLICIT_BZERO)
diff --git a/cmake/dependencies/system/fuse.cmake b/cmake/dependencies/system/fuse.cmake
new file mode 100644
index 00000000..7de12b31
--- /dev/null
+++ b/cmake/dependencies/system/fuse.cmake
@@ -0,0 +1,44 @@
+# Try pkg-config first, fall back to find_library
+if(PkgConfig_FOUND)
+  pkg_check_modules(FUSE QUIET IMPORTED_TARGET fuse>=2.6)
+  if(FUSE_FOUND AND NOT TARGET Fuse::Fuse)
+    add_library(Fuse::Fuse ALIAS PkgConfig::FUSE)
+  endif()
+endif()
+
+if(NOT FUSE_FOUND)
+  find_library(FUSE_LIBRARIES fuse QUIET)
+  if(FUSE_LIBRARIES)
+    set(FUSE_FOUND TRUE)
+    if(NOT TARGET Fuse::Fuse)
+      add_library(Fuse::Fuse UNKNOWN IMPORTED)
+      set_target_properties(Fuse::Fuse PROPERTIES
+        IMPORTED_LOCATION "${FUSE_LIBRARIES}")
+    endif()
+  endif()
+endif()
+
+if(FUSE_FOUND)
+  set(DISABLE_FUSE FALSE CACHE BOOL "Disable FUSE support")
+  if(NOT DISABLE_FUSE)
+    if(FUSE_VERSION)
+      message(STATUS "FUSE support enabled (version ${FUSE_VERSION})")
+    else()
+      message(STATUS "FUSE support enabled")
+    endif()
+    # FUSE_PREFIX is set in cmake/config/global.cmake
+    set(HAVE_FUSE TRUE CACHE INTERNAL "FUSE filesystem support available")
+  else()
+    message(STATUS "FUSE support disabled by user")
+    unset(HAVE_FUSE CACHE)
+  endif()
+else()
+  message(STATUS "Install FUSE version >= 2.6 to enable RIB access")
+  unset(HAVE_FUSE CACHE)
+endif()
+
+if(NOT HAVE_FUSE)
+  set(FUSE_LIBRARIES "")
+endif()
+
+mark_as_advanced(FUSE_LIBRARIES)
diff --git a/cmake/dependencies/system/libraries.cmake b/cmake/dependencies/system/libraries.cmake
new file mode 100644
index 00000000..55c22d6a
--- /dev/null
+++ b/cmake/dependencies/system/libraries.cmake
@@ -0,0 +1,17 @@
+if(NOT APPLE)
+  find_library(LIBRT_LIBRARIES rt)
+  mark_as_advanced(LIBRT_LIBRARIES)
+  if(NOT LIBRT_LIBRARIES)
+    message(FATAL_ERROR "Could not find librt")
+  endif()
+else()
+  set(LIBRT_LIBRARIES "")
+endif()
+
+find_package(Threads REQUIRED)
+
+find_library(LIBM_LIBRARIES m)
+mark_as_advanced(LIBM_LIBRARIES)
+if(NOT LIBM_LIBRARIES)
+  message(FATAL_ERROR "Could not find libm")
+endif()
diff --git a/cmake/dependencies/system/protobufc.cmake b/cmake/dependencies/system/protobufc.cmake
new file mode 100644
index 00000000..b7e0062a
--- /dev/null
+++ b/cmake/dependencies/system/protobufc.cmake
@@ -0,0 +1,13 @@
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/utils")
+
+find_package(ProtobufC QUIET)
+if(NOT (PROTOBUF_C_INCLUDE_DIRS AND PROTOBUF_C_LIBRARY
+         AND PROTOBUF_PROTOC_C_EXECUTABLE))
+  message(FATAL_ERROR "Protobuf C compiler required but not found. "
+                      "Please install Google Protocol Buffers.")
+else()
+  message(STATUS "Found protobuf C compiler in ${PROTOBUF_PROTOC_C_EXECUTABLE}")
+endif()
+
+# Note: Include dirs are added per-target via target_include_directories
+# using ${PROTOBUF_C_INCLUDE_DIRS}
diff --git a/cmake/dependencies/system/robustmutex.cmake b/cmake/dependencies/system/robustmutex.cmake
new file mode 100644
index 00000000..89b7325b
--- /dev/null
+++ b/cmake/dependencies/system/robustmutex.cmake
@@ -0,0 +1,18 @@
+list(APPEND CMAKE_REQUIRED_DEFINITIONS -D_POSIX_C_SOURCE=200809L)
+list(APPEND CMAKE_REQUIRED_DEFINITIONS -D__XSI_VISIBLE=500)
+list(APPEND CMAKE_REQUIRED_LIBRARIES pthread)
+check_symbol_exists(pthread_mutexattr_setrobust pthread.h HAVE_ROBUST_MUTEX)
+
+if(HAVE_ROBUST_MUTEX)
+  set(DISABLE_ROBUST_MUTEXES FALSE CACHE BOOL "Disable robust mutex support")
+  if(NOT DISABLE_ROBUST_MUTEXES)
+    message(STATUS "Robust mutex support enabled")
+    set(HAVE_ROBUST_MUTEX TRUE)
+  else()
+    message(STATUS "Robust mutex support disabled by user")
+    unset(HAVE_ROBUST_MUTEX)
+  endif()
+else()
+  message(STATUS "Robust mutex support not available")
+  unset(HAVE_ROBUST_MUTEX)
+endif()
diff --git a/cmake/dependencies/system/sysrandom.cmake b/cmake/dependencies/system/sysrandom.cmake
new file mode 100644
index 00000000..dc8443a1
--- /dev/null
+++ b/cmake/dependencies/system/sysrandom.cmake
@@ -0,0 +1,14 @@
+if(APPLE OR CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
+  set(SYS_RND_HDR "")
+else()
+  find_path(SYS_RND_HDR sys/random.h PATH /usr/include/ /usr/local/include/)
+  if(SYS_RND_HDR)
+    message(STATUS "Found sys/random.h in ${SYS_RND_HDR}")
+    set(HAVE_SYS_RANDOM TRUE)
+  else()
+    set(SYS_RND_HDR "")
+    unset(HAVE_SYS_RANDOM)
+  endif()
+endif()
+
+mark_as_advanced(SYS_RND_HDR)