diff --git a/academic/ITK/ITK.SlackBuild b/academic/ITK/ITK.SlackBuild
index afd0f0cc99..bc13af67ce 100644
--- a/academic/ITK/ITK.SlackBuild
+++ b/academic/ITK/ITK.SlackBuild
@@ -85,7 +85,7 @@ find -L . \
 patch -p1 <<'endpatch'
 --- InsightToolkit-4.13.2/Modules/ThirdParty/VNL/src/vxl/vcl/vcl_compiler.h.cp
 +++ InsightToolkit-4.13.2/Modules/ThirdParty/VNL/src/vxl/vcl/vcl_compiler.h
-@@ -96,6 +96,28 @@
+@@ -96,6 +96,39 @@
  #   define VCL_GCC_81
  #  else
  #   define VCL_GCC_80
@@ -111,6 +111,17 @@ patch -p1 <<'endpatch'
 +#   define VCL_GCC_101
 +#  else
 +#   define VCL_GCC_100
++#  endif
++# elif (__GNUC__==11)
++#  define VCL_GCC_11
++#  if (__GNUC_MINOR__ > 2 )
++#   define VCL_GCC_113
++#  elif (__GNUC_MINOR__ > 1 )
++#   define VCL_GCC_112
++#  elif (__GNUC_MINOR__ > 0 )
++#   define VCL_GCC_111
++#  else
++#   define VCL_GCC_110
  #  endif
  # else
  #  error "Dunno about this gcc"