chore: promoted the make placeholder to full article

knowledge base/gnu userland/make.md

@@ -0,0 +1,103 @@
+# GNU Make
+
+1. [TL;DR](#tldr)
+1. [Further readings](#further-readings)
+1. [Sources](#sources)
+
+## TL;DR
+
+```makefile
+# assign default values, but allow override
+# usage: make override_me=new_value target
+override override_me ?= default_value
+
+
+# export variables for all programs to see
+# only exported in the commands' sub-shells
+export
+
+# export specific variables only
+export override_me
+
+
+# assign shell command output as values
+command_output = ${shell command with args}
+
+
+target_name: target_specific_variable = value
+target_name: dash_instead_of_underscore = ${subst _,-,${override_me}}
+target_name: previous_target required_file.ext
+    ${info output string}
+    echoed_command
+    @quiet_command
+    ${MAKE} next_target
+
+previous_target:
+    @quiet_command
+
+next_target:
+
+
+# load env files
+-include .env
+-include .env.local
+
+
+# conditionals
+ifeq "${shell uname}" "Darwin"
+expiration_date = ${shell date -v "+365d" "+%FT%TZ"}
+else ifeq "${shell uname}" "Linux"
+expiration_date = ${shell date -d "+1 year" "+%FT%TZ"}
+endif
+```
+
+```makefile
+repository_name = $(shell basename $$(git rev-parse --show-toplevel))
+
+override environment_id ?= dev
+override tf_plan_file ?= ${environment_id}.tfplan
+override tf_vars_file ?= ${environment_id}.tfvars
+
+-include .env
+export
+
+pre-flight:
+    ${info validating terraform's configuration…}
+    @terraform fmt -recursive
+    @terraform validate
+
+ifeq "${destroy}" "1"
+tf_destroy_switch = -destroy
+endif
+
+plan: pre-flight ${tf_vars_file}
+    ${info planning ${environment_id}'s resources…}
+    @terraform plan ${tf_destroy_switch} -var-file='${tf_vars_file}' -input=false -out='${tf_plan_file}'
+
+apply: plan ${tf_plan_file}
+    ${info applying ${environment_id}'s plan}
+    @terraform apply '${tf_plan_file}'
+```
+
+## Further readings
+
+- [Conditional syntax]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+- [Makefile variable initialization and export]
+
+<!--
+  References
+  -->
+
+<!-- Upstream -->
+[conditional syntax]: https://www.gnu.org/software/make/manual/html_node/Conditional-Syntax.html
+
+<!-- In-article sections -->
+[further readings]: #further-readings
+
+<!-- Others -->
+[makefile variable initialization and export]: https://stackoverflow.com/questions/2838715/makefile-variable-initialization-and-export

knowledge base/make.placeholder

@@ -1,15 +0,0 @@
-```makefile
-# make override_me=new_value target
-override override_me ?= default_value
-
-target_name: target_specific_variable = value
-target_name: previous_target required_file.ext
-    echoed_command
-    @quiet_command
-    ${MAKE} next_target
-
-previous_target:
-    @quiet_command
-
-next_target:
-```