dist/tools: Check BOARD_INSUFFICIENT_MEMORY usage

Enforce BOARD_INSUFFICIENT_MEMORY is not managed in the Makefile in the examples

dist/tools/buildsystem_sanity_check/check.sh

@@ -172,6 +172,20 @@ check_not_setting_board_equal() {
         | error_with_message 'Applications Makefile should use "BOARD ?="'
 }
 
+# Examples must not provide BOARD_INSUFFICIENT_MEMORY in Makefile, but in
+# Makefile.ci
+check_board_insufficient_memory_not_in_makefile() {
+    local patterns=()
+    local pathspec=()
+
+    patterns+=(-e '^[[:space:]]*BOARD_INSUFFICIENT_MEMORY[[:space:]:]*=')
+
+    pathspec+=('examples*/Makefile')
+
+    git -C "${RIOTBASE}" grep "${patterns[@]}" -- "${pathspec[@]}" \
+        | error_with_message 'Move BOARD_INSUFFICIENT_MEMORY to Makefile.ci'
+}
+
 error_on_input() {
     ! grep ''
 }
@@ -183,6 +197,7 @@ all_checks() {
     check_board_do_not_include_cpu_features_dep
     check_cpu_cpu_model_defined_in_makefile_features
     check_not_setting_board_equal
+    check_board_insufficient_memory_not_in_makefile
 }
 
 main() {