Fix incompatibility with multi-config cmake generator

Avoid hard coding the path of zig2 relative to PROJECT_BINARY_DIR

Author: melonedo

CMakeLists.txt

@@ -983,11 +983,7 @@ add_custom_command(
   WORKING_DIRECTORY "${ZIG2_WORKING_DIR}"
 )
 
-if(WIN32)
-  set(ZIG_EXECUTABLE "${PROJECT_BINARY_DIR}/zig2.exe")
-else()
-  set(ZIG_EXECUTABLE "${PROJECT_BINARY_DIR}/zig2")
-endif()
+set(ZIG_EXECUTABLE "$<TARGET_FILE:zig2>")
 
 install(CODE "set(ZIG_EXECUTABLE \"${ZIG_EXECUTABLE}\")")
 install(CODE "set(ZIG_BUILD_ARGS \"${ZIG_BUILD_ARGS}\")")