Fix Linux clone crashes from leaked Iconv discovery

Author: tamlok

AGENTS.md

@@ -132,6 +132,13 @@ $env:VXCORE_LOG_LEVEL="trace"; $env:VXCORE_LOG_FILE="C:\Temp\vxcore.log"; .\myap
 
 ## Build Commands
 
+Keep vxcore's `find_package(Iconv REQUIRED)` **after** `add_subdirectory(third_party)`
+and before `src`/`tests`. Earlier discovery leaks `ICONV_FOUND` into libgit2 and
+enables its Unicode precomposition code on Linux, where directory iterator cleanup
+can call `iconv_close` on an uninitialized handle. Discovery must remain in the root
+scope because both vxcore and the standalone `test_simple_search_backend` use
+`Iconv::Iconv`. Clone and search tests cover both sides of this dependency.
+
 ```bash
 # Configure
 cmake -B build -DVXCORE_BUILD_TESTS=ON

CMakeLists.txt

@@ -30,10 +30,6 @@ find_package(Threads REQUIRED)
 if(UNIX AND NOT APPLE)
     find_package(OpenSSL REQUIRED)
 endif()
-if(NOT WIN32)
-    find_package(Iconv REQUIRED)
-endif()
-
 
 # MSVC: enable C++ exception unwinding (/EHsc). Without this, try/catch blocks
 # emit C4530 warnings AND don't actually unwind at runtime — uncaught exceptions
@@ -53,6 +49,14 @@ set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 
 add_subdirectory(third_party)
+
+# Discover Iconv after libgit2: leaking ICONV_FOUND into its configuration
+# enables Unicode precomposition on Linux and can close an uninitialized handle.
+# Keep the imported target in this scope for both src and standalone tests.
+if(NOT WIN32)
+    find_package(Iconv REQUIRED)
+endif()
+
 add_subdirectory(src)
 
 if(VXCORE_BUILD_CLI)