feat: add option to use system-installed jwt-cpp

Add ZM_USE_SYSTEM_JWT_CPP CMake option (default OFF) to allow using
system-installed jwt-cpp instead of the vendored version. When enabled,
CMake will search for jwt-cpp via find_package(jwt-cpp CONFIG).

The vendored jwt-cpp in dep/ is only built when not using system version.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CMakeLists.txt

@@ -247,6 +247,10 @@ if(NOT ZM_JWT_BACKEND IN_LIST ZM_JWT_BACKEND_OPTIONS)
   message(FATAL_ERROR "Invalid value for ZM_JWT_BACKEND. Possible options: ${ZM_JWT_BACKEND_OPTIONS}")
 endif()
 
+# Option to use system-installed jwt-cpp instead of vendored version
+set(ZM_USE_SYSTEM_JWT_CPP "OFF" CACHE BOOL
+  "Set to ON to use system-installed jwt-cpp instead of the vendored version. default: OFF")
+
 if((ZM_TARGET_DISTRO MATCHES "^el") OR (ZM_TARGET_DISTRO MATCHES "^fc"))
   set(ZM_RUNDIR "/run/zoneminder")
   set(ZM_SOCKDIR "/var/lib/zoneminder/sock")
@@ -397,6 +401,24 @@ if (${ZM_JWT_BACKEND} STREQUAL "libjwt")
   endif()
 endif()
 
+# jwt-cpp (system or vendored)
+if (${ZM_JWT_BACKEND} STREQUAL "jwt_cpp")
+  if(ZM_USE_SYSTEM_JWT_CPP)
+    find_package(jwt-cpp CONFIG REQUIRED)
+    if(TARGET jwt-cpp::jwt-cpp)
+      set(HAVE_SYSTEM_JWT_CPP 1)
+      set(optlibsfound "${optlibsfound} jwt-cpp(system)")
+      message(STATUS "Using system-installed jwt-cpp")
+    else()
+      message(FATAL_ERROR "System jwt-cpp requested but jwt-cpp::jwt-cpp target not found")
+    endif()
+  else()
+    set(HAVE_SYSTEM_JWT_CPP 0)
+    set(optlibsfound "${optlibsfound} jwt-cpp(vendored)")
+    message(STATUS "Using vendored jwt-cpp")
+  endif()
+endif()
+
 # GnuTLS
 if (${ZM_CRYPTO_BACKEND} STREQUAL "gnutls")
   find_library(GNUTLS_LIBRARIES gnutls REQUIRED)

dep/CMakeLists.txt

@@ -1,4 +1,7 @@
-add_subdirectory(jwt-cpp)
+# Only build vendored jwt-cpp if not using system-installed version
+if(NOT HAVE_SYSTEM_JWT_CPP)
+  add_subdirectory(jwt-cpp)
+endif()
 add_subdirectory(libbcrypt)
 add_subdirectory(RtspServer)
 add_subdirectory(span-lite)