Added support for custom OpenSSL selection

Author: toxicteddy00077

CMakeLists.txt

@@ -764,14 +764,36 @@ endif()
 if(QUIC_TLS_LIB STREQUAL "quictls" OR QUIC_TLS_LIB STREQUAL "openssl")
     add_library(OpenSSL INTERFACE)
 
-    include(FetchContent)
+    option(QUIC_USE_EXTERNAL_OPENSSL "Use external OpenSSL instead of building from submodules" OFF)
+    set(QUIC_OPENSSL_INCLUDE_DIR "" CACHE PATH "Path to OpenSSL include directory")
+    set(QUIC_OPENSSL_LIB_DIR "" CACHE PATH "Path to OpenSSL library directory")
+
+    if(QUIC_USE_EXTERNAL_OPENSSL OR QUIC_OPENSSL_INCLUDE_DIR OR QUIC_OPENSSL_LIB_DIR)
+        add_library(OpenSSLQuic INTERFACE)
+        if(QUIC_OPENSSL_INCLUDE_DIR AND QUIC_OPENSSL_LIB_DIR)
+            target_include_directories(OpenSSLQuic INTERFACE ${QUIC_OPENSSL_INCLUDE_DIR})
+            find_library(LIB_CRYPTO NAMES crypto libcrypto PATHS ${QUIC_OPENSSL_LIB_DIR} NO_DEFAULT_PATH REQUIRED)
+            find_library(LIB_SSL NAMES ssl libssl PATHS ${QUIC_OPENSSL_LIB_DIR} NO_DEFAULT_PATH REQUIRED)
+            target_link_libraries(OpenSSLQuic INTERFACE ${LIB_SSL} ${LIB_CRYPTO})
+        else()
+            if(QUIC_TLS_LIB STREQUAL "openssl")
+                find_package(OpenSSL 3.5.0 REQUIRED)
+            else()
+                find_package(OpenSSL REQUIRED)
+            endif()
+            target_link_libraries(OpenSSLQuic INTERFACE OpenSSL::SSL OpenSSL::Crypto)
+        endif()
+        add_library(OpenSSLQuic::OpenSSLQuic ALIAS OpenSSLQuic)
+    else()
+        include(FetchContent)
 
-    FetchContent_Declare(
-        OpenSSLQuic
-        SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/submodules
-        CMAKE_ARGS "-DQUIC_USE_SYSTEM_LIBCRYPTO=${QUIC_USE_SYSTEM_LIBCRYPTO}"
-    )
-    FetchContent_MakeAvailable(OpenSSLQuic)
+        FetchContent_Declare(
+            OpenSSLQuic
+            SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/submodules
+            CMAKE_ARGS "-DQUIC_USE_SYSTEM_LIBCRYPTO=${QUIC_USE_SYSTEM_LIBCRYPTO}"
+        )
+        FetchContent_MakeAvailable(OpenSSLQuic)
+    endif()
 
     target_link_libraries(OpenSSL
         INTERFACE