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, 4 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)