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>

1 files changed, 13 insertions, 0 deletions

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}