From: Xiangzhe <xiangzhedev@gmail.com>
Subject: [PATCH] build: use system copies of packaged dependencies

Gentoo provides compatible CMake packages for Catch2, cpp-httplib,
cxxopts, nlohmann_json, and SimpleIni. Use their imported targets in the
DISABLE_VCPKG build instead of compiling the bundled snapshots.

SimpleIni is consumed by TerminalCommon and directly by etserver, so link its
header-only imported target through those targets rather than relying on a
global include directory.

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -140,27 +140,20 @@

 if(DISABLE_VCPKG)
   if(BUILD_TESTING)
-    add_subdirectory(${EXTERNAL_DIR}/Catch2)
-  endif()
-  add_subdirectory(${EXTERNAL_DIR}/cxxopts)
-  add_subdirectory(${EXTERNAL_DIR}/cpp-httplib)
-  add_subdirectory(${EXTERNAL_DIR}/json)
-  include_directories(
-    SYSTEM ${EXTERNAL_DIR}/cpp-httplib
-  )
-  include_directories(
-    ${EXTERNAL_DIR}/simpleini
-    ${EXTERNAL_DIR}/json/include
-    ${EXTERNAL_DIR}/cxxopts/include
-  )
-else()
-  if(BUILD_TESTING)
-    find_package(Catch2 CONFIG REQUIRED)
+    find_package(Catch2 3 CONFIG REQUIRED)
   endif()
   find_package(httplib CONFIG REQUIRED)
   find_package(cxxopts CONFIG REQUIRED)
   find_package(nlohmann_json CONFIG REQUIRED)
-  find_path(SIMPLEINI_INCLUDE_DIRS "ConvertUTF.c")
+  find_package(SimpleIni CONFIG REQUIRED)
+else()
+  if(BUILD_TESTING)
+    find_package(Catch2 3 CONFIG REQUIRED)
+  endif()
+  find_package(httplib CONFIG REQUIRED)
+  find_package(cxxopts CONFIG REQUIRED)
+  find_package(nlohmann_json CONFIG REQUIRED)
+  find_package(SimpleIni CONFIG REQUIRED)
 endif()

 # Optional packages
@@ -388,7 +381,6 @@
   ${UTEMPTER_INCLUDE_DIR}
   ${Boost_INCLUDE_DIR}
   ${OPENSSL_INCLUDE_DIR}
-  ${SIMPLEINI_INCLUDE_DIRS}
 )

 if(NOT ANDROID)
@@ -471,6 +463,7 @@
   ${ETERMINAL_SRCS}
   ${ETERMINAL_HDRS})
 add_dependencies(TerminalCommon generated-code et-lib)
+target_link_libraries(TerminalCommon PUBLIC SimpleIni::SimpleIni)
 decorate_target(TerminalCommon)

 add_executable(et src/terminal/TerminalClientMain.cpp)
@@ -501,6 +494,7 @@
   target_link_libraries(
     etserver
     LINK_PUBLIC
+    SimpleIni::SimpleIni
     TerminalCommon
     et-lib
     ${CMAKE_THREAD_LIBS_INIT}