build now works on nix

1. Static linking - Added KTE_STATIC_LINK CMake option and
   disabled it in default.nix to avoid the "attempted
   static link of dynamic object" error

2. Missing include - Added <cstring> to
   test_swap_edge_cases.cc for std::memset/std::memcpy (GCC
   14 is stricter about transitive includes)

CMakeLists.txt

@@ -14,6 +14,7 @@ set(BUILD_TESTS ON CACHE BOOL "Enable building test programs.")
 set(KTE_FONT_SIZE "18.0" CACHE STRING "Default font size for GUI")
 option(KTE_UNDO_DEBUG "Enable undo instrumentation logs" OFF)
 option(KTE_ENABLE_TREESITTER "Enable optional Tree-sitter highlighter adapter" OFF)
+option(KTE_STATIC_LINK "Enable static linking on Linux" ON)
 
 # Optionally enable AddressSanitizer (ASan)
 option(ENABLE_ASAN "Enable AddressSanitizer for builds" OFF)
@@ -285,7 +286,7 @@ endif ()
 target_link_libraries(kte ${CURSES_LIBRARIES})
 
 # Static linking on Linux only (macOS does not support static linking of system libraries)
-if (NOT APPLE)
+if (NOT APPLE AND KTE_STATIC_LINK)
     target_link_options(kte PRIVATE -static)
 endif ()
 
@@ -375,7 +376,7 @@ if (BUILD_TESTS)
     endif ()
 
     # Static linking on Linux only (macOS does not support static linking of system libraries)
-    if (NOT APPLE)
+    if (NOT APPLE AND KTE_STATIC_LINK)
         target_link_options(kte_tests PRIVATE -static)
     endif ()
 endif ()
@@ -418,7 +419,7 @@ if (BUILD_GUI)
     endif ()
 
     # Static linking on Linux only (macOS does not support static linking of system libraries)
-    if (NOT APPLE)
+    if (NOT APPLE AND KTE_STATIC_LINK)
         target_link_options(kge PRIVATE -static)
     endif ()
 

default.nix

@@ -48,6 +48,7 @@ stdenv.mkDerivation {
     "-DBUILD_GUI=${if graphical then "ON" else "OFF"}"
     "-DKTE_USE_QT=${if graphical-qt then "ON" else "OFF"}"
     "-DCMAKE_BUILD_TYPE=Debug"
+    "-DKTE_STATIC_LINK=OFF"
   ];
 
   installPhase = ''

tests/test_swap_edge_cases.cc

@@ -5,6 +5,7 @@
 
 #include <cstdint>
 #include <cstdio>
+#include <cstring>
 #include <fstream>
 #include <string>
 #include <vector>