build/cmake: add appropriate llhttp flags to opendht.pc

CMakeLists.txt

@@ -105,6 +105,9 @@ endif ()
 
 list (APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")
 if (NOT MSVC)
+    # Initialize pkg-config substitution variables for llhttp before any detection
+    set(http_lib "")
+    set(llhttp_lib "")
     # Generalized UNIX/MSYS2 build pipeline
     set (THREADS_PREFER_PTHREAD_FLAG TRUE)
     find_package (Threads)
@@ -153,8 +156,9 @@ if (NOT MSVC)
         if (OPENDHT_HTTP)
             pkg_search_module(LLHTTP IMPORTED_TARGET llhttp libllhttp)
             if (LLHTTP_FOUND)
-                message(STATUS "Found llhttp: ${LLHTTP_FOUND} ${LLHTTP_INCLUDE_DIR}")
+                message(STATUS "Found llhttp: ${LLHTTP_FOUND} ${LLHTTP_INCLUDE_DIR} (module: ${LLHTTP_MODULE_NAME})")
                 set(llhttp_target PkgConfig::LLHTTP)
+                set(llhttp_lib ", ${LLHTTP_MODULE_NAME}")
             else()
                 message(STATUS "llhttp not found with pkgconfig")
             endif()
@@ -196,6 +200,7 @@ if (NOT MSVC)
         if (OPENDHT_HTTP)
             find_package(llhttp CONFIG REQUIRED)
             set(llhttp_target llhttp::llhttp_static)
+            set(http_lib "-lllhttp")
             if (OPENDHT_PROXY_OPENSSL)
                 find_package(openssl REQUIRED)
             endif()
@@ -244,6 +249,9 @@ if (NOT MSVC)
                 INTERFACE_INCLUDE_DIRECTORIES ${LLHTTP_INCLUDE_DIR}
             )
             set(llhttp_target llhttp_static)
+            if (NOT llhttp_lib)
+                set(http_lib "-lllhttp")
+            endif()
         elseif (OPENDHT_DOWNLOAD_DEPS)
             message(STATUS "Fallback mode specified, downloading llhttp")
             FetchContent_Declare(llhttp-local REQUIRED
@@ -263,6 +271,9 @@ if (NOT MSVC)
             else()
                 set(llhttp_target llhttp_static)
             endif()
+            if (NOT llhttp_lib)
+                set(http_lib "-lllhttp")
+            endif()
         else()
             message(SEND_ERROR "llhttp not found and fallback downloader disabled. Install llhttp or use OPENDHT_DOWNLOAD_DEPS option")
         endif ()

opendht.pc.in

@@ -8,5 +8,5 @@ Version: @VERSION@
 Libs: -L${libdir} -lopendht
 Libs.private: @http_lib@ -pthread
 Requires: gnutls >= 3.3@jsoncpp_lib@@openssl_lib@
-Requires.private: nettle >= 2.4@argon2_lib@@iouring_lib@
+Requires.private: nettle >= 2.4@argon2_lib@@llhttp_lib@@iouring_lib@
 Cflags: -I${includedir}