Refine Kconfig integration and build system

[jserv]

This converts tools/kconfig to git submodule pointing to the refined one [1], integrates Kbuild toolchain detection functions for automatic dependency checking, and tweaks build system to prevent unnecessary compilation when invalid targets are specified.

• Add Kbuild $(success,...) functions to detect SDL2, Pixman, libpng, libjpeg
• Add dependency clauses to backend and loader options

[1] https://github.com/sysprog21/Kconfiglib

[cubic-dev-ai]

3 issues found across 17 files

Prompt for AI agents (all 3 issues)

Understand the root cause of the following 3 issues and fix them.


<file name="configs/Kconfig">

<violation number="1" location="configs/Kconfig:9">
`def_bool` cannot invoke Make functions like `$(success,...)`; this introduces invalid syntax and causes Kconfig parsing to fail. Please replace the defaults with a valid Kconfig mechanism (e.g., deriving the value from another symbol or environment option).</violation>
</file>

<file name="mk/common.mk">

<violation number="1" location="mk/common.mk:685">
This condition only checks whether any goal is known. If a user runs a mix of known and unknown targets (e.g. `make foo clean`), `$(filter ...)` returns `clean`, so the block still includes `$(target-depends)` and the build fails with missing .d files. The guard needs to verify that **all** goals are known before including dependencies.</violation>
</file>

<file name="Makefile">

<violation number="1" location="Makefile:9">
Skipping mk/common.mk whenever config/defconfig appears in MAKECMDGOALS means multi-goal invocations like &quot;make defconfig all&quot; can no longer build because the core rules are never included.</violation>
</file>

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[cubic-dev-ai]

def_bool cannot invoke Make functions like $(success,...); this introduces invalid syntax and causes Kconfig parsing to fail. Please replace the defaults with a valid Kconfig mechanism (e.g., deriving the value from another symbol or environment option).

Prompt for AI agents

Address the following comment on configs/Kconfig at line 9:

<comment>`def_bool` cannot invoke Make functions like `$(success,...)`; this introduces invalid syntax and causes Kconfig parsing to fail. Please replace the defaults with a valid Kconfig mechanism (e.g., deriving the value from another symbol or environment option).</comment>

<file context>
@@ -4,6 +4,19 @@ config CONFIGURED
 
+# Dependency detection using Kbuild toolchain functions
+config HAVE_SDL2
+    def_bool $(success,pkg-config --exists sdl2)
+
+config HAVE_PIXMAN
</file context>

[cubic-dev-ai]

This condition only checks whether any goal is known. If a user runs a mix of known and unknown targets (e.g. make foo clean), $(filter ...) returns clean, so the block still includes $(target-depends) and the build fails with missing .d files. The guard needs to verify that all goals are known before including dependencies.

Prompt for AI agents

Address the following comment on mk/common.mk at line 685:

<comment>This condition only checks whether any goal is known. If a user runs a mix of known and unknown targets (e.g. `make foo clean`), `$(filter ...)` returns `clean`, so the block still includes `$(target-depends)` and the build fails with missing .d files. The guard needs to verify that **all** goals are known before including dependencies.</comment>

<file context>
@@ -678,6 +678,17 @@ clean: __FORCE
+build-goals := all clean $(target-builds)
+ifneq ($(MAKECMDGOALS),)
+    # MAKECMDGOALS is not empty, check if it&#39;s a known target
+    ifneq ($(filter $(MAKECMDGOALS),$(build-goals)),)
+        # Known target, include dependencies (except for clean)
+        ifneq &quot;$(MAKECMDGOALS)&quot; &quot;clean&quot;
</file context>

Suggested change

	ifneq ($(filter $(MAKECMDGOALS),$(build-goals)),)
	ifeq ($(filter-out $(build-goals),$(MAKECMDGOALS)),)

[cubic-dev-ai]

Skipping mk/common.mk whenever config/defconfig appears in MAKECMDGOALS means multi-goal invocations like "make defconfig all" can no longer build because the core rules are never included.

Prompt for AI agents

Address the following comment on Makefile at line 9:

<comment>Skipping mk/common.mk whenever config/defconfig appears in MAKECMDGOALS means multi-goal invocations like &quot;make defconfig all&quot; can no longer build because the core rules are never included.</comment>

<file context>
@@ -1,13 +1,18 @@
-ifneq &quot;$(CONFIG_CONFIGURED)&quot; &quot;y&quot;
-$(error You must first run &#39;make config&#39;)
-endif
+ifeq ($(filter $(check_goal),config defconfig),)
+    ifneq &quot;$(CONFIG_CONFIGURED)&quot; &quot;y&quot;
+        $(error You must first run &#39;make config&#39; or &#39;make defconfig&#39;)
</file context>