In Gentoo rocm_agent_enumerator is installed by rocminfo and is in PATH.

--- catch/CMakeLists.txt~	2023-11-18 13:56:08.000000000 +0800
+++ catch/CMakeLists.txt	2023-11-18 13:59:28.136170638 +0800
@@ -182,9 +182,8 @@
 # rocm_agent_enumerator
 if(NOT DEFINED OFFLOAD_ARCH_STR
    AND NOT DEFINED ENV{HCC_AMDGPU_TARGET}
-   AND EXISTS "${ROCM_PATH}/bin/rocm_agent_enumerator"
    AND HIP_PLATFORM STREQUAL "amd" AND UNIX)
-    execute_process(COMMAND ${ROCM_PATH}/bin/rocm_agent_enumerator
+    execute_process(COMMAND rocm_agent_enumerator
          OUTPUT_VARIABLE HIP_GPU_ARCH
          RESULT_VARIABLE ROCM_AGENT_ENUM_RESULT)
     # Trim out gfx000