docs: add env var description

Author: kgryte

tools/make/lib/install/addons.mk

@@ -55,10 +55,18 @@ install_node_addons_list_addons_flags := "--pattern $(node_addons_pattern)"
 #
 # ## Notes
 #
-# -   If unable to install a native add-on, the target prints an error message and proceeds to try installing the next add-on.
+# -   When `FAST_FAIL` is `0`, if unable to install a native add-on, the recipe prints an error message and proceeds to try installing the next add-on.
+#
+# @param {integer} [FAST_FAIL] - flag indicating whether to immediately exit if unable to install a native add-on (default: 1)
 #
 # @example
 # make install-node-addons
+#
+# @example
+# FAST_FAIL=0 make install-node-addons
+#
+# @example
+# FAST_FAIL=1 make install-node-addons
 #/
 install-node-addons: $(NODE_MODULES) clean-node-addons
 ifeq ($(FAIL_FAST), true)
@@ -96,8 +104,20 @@ endif
 #/
 # Removes all compiled and generated files for Node.js native add-ons.
 #
+# ## Notes
+#
+# -   When `FAST_FAIL` is `0`, if unable to clean a native add-on, the recipe prints an error message and proceeds to try cleaning the next add-on.
+#
+# @param {integer} [FAST_FAIL] - flag indicating whether to immediately exit if unable to clean a native add-on (default: 1)
+#
 # @example
 # make clean-node-addons
+#
+# @example
+# FAST_FAIL=0 make clean-node-addons
+#
+# @example
+# FAST_FAIL=1 make clean-node-addons
 #/
 clean-node-addons: $(NODE_MODULES)
 ifeq ($(FAIL_FAST), true)