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, 35 insertions, 0 deletions

diff --git a/cmake/dependencies/crypt/openssl.cmake b/cmake/dependencies/crypt/openssl.cmake
new file mode 100644
index 00000000..ed07cc9d
--- /dev/null
+++ b/cmake/dependencies/crypt/openssl.cmake
@@ -0,0 +1,35 @@
+find_package(OpenSSL QUIET)
+if(OPENSSL_FOUND)
+  set(HAVE_OPENSSL_RNG TRUE)
+  if(OPENSSL_VERSION VERSION_LESS "3.0.0")
+    message(STATUS "Install version >= 3.0.0 to enable OpenSSL support "
+                   "(found version \"${OPENSSL_VERSION}\")")
+  else()
+    set(DISABLE_OPENSSL FALSE CACHE BOOL "Disable OpenSSL support")
+    if(NOT DISABLE_OPENSSL)
+      message(STATUS "OpenSSL support enabled, found version ${OPENSSL_VERSION}")
+      set(HAVE_OPENSSL TRUE CACHE INTERNAL "OpenSSL cryptography support available")
+      set(DISABLE_PQC FALSE CACHE BOOL "Disable post-quantum cryptography support")
+      if(OPENSSL_VERSION VERSION_GREATER_EQUAL "3.4.0")
+        if(NOT DISABLE_PQC)
+          set(HAVE_OPENSSL_PQC TRUE CACHE INTERNAL "OpenSSL post-quantum cryptography available")
+          message(STATUS "OpenSSL PQC support enabled")
+        else()
+          message(STATUS "OpenSSL PQC support disabled by user")
+          unset(HAVE_OPENSSL_PQC CACHE)
+        endif()
+      else()
+        message(STATUS "Install OpenSSL >= 3.4.0 for PQC support")
+      endif()
+    else()
+      message(STATUS "OpenSSL support disabled")
+      unset(HAVE_OPENSSL CACHE)
+    endif()
+  endif()
+else()
+  message(STATUS "Install OpenSSL version >= 3.0.0 to enable OpenSSL support")
+  unset(HAVE_OPENSSL_RNG)
+  unset(HAVE_OPENSSL CACHE)
+endif()
+
+# Secure memory options are in cmake/config/global.cmake