Add the vendored dependencies whether or not libakgl is top-level

Embedded with add_subdirectory(), the deps/ submodules a recursive clone
just checked out were ignored and find_package(SDL3 REQUIRED) ran instead,
so configure failed on a machine with nothing installed. Each dependency is
now added by akgl_add_vendored_dependency(), which skips it when the target
is already declared or the submodule is missing; the find_package lookups
run afterwards for whatever is left. The CTest suppression moves with them
and is lifted before this project registers its own suites.

Two consequences of the move: pkg-config is only looked for when something
has to come from the system, and the build-tree RPATH keys on whether
anything was vendored rather than on being the top-level project, so an
embedded build's tests can find the satellite libraries too.

Verified by configuring and building a consumer that embeds this repository
with CMAKE_DISABLE_FIND_PACKAGE_* set for all seven dependencies.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CMakeLists.txt

@@ -14,10 +14,10 @@ if(AKGL_COVERAGE)
   find_program(GCOVR_EXECUTABLE gcovr REQUIRED)
 endif()
 
-if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+# Vendored projects own their test suites. Suppress their CTest registration so
-
+# the suite that runs contains only the targets built here. The override is
-# Vendored projects own their test suites. Suppress their CTest registration
+# lifted again below, before this project registers its own tests, so an
-# while embedded so the top-level suite contains only targets built here.
+# embedding consumer's add_test() still reaches CTest.
 set(AKGL_SUPPRESS_DEPENDENCY_TESTS TRUE)
 function(add_test)
   if(NOT AKGL_SUPPRESS_DEPENDENCY_TESTS)
@@ -34,53 +34,79 @@ set(JANSSON_WITHOUT_TESTS ON CACHE BOOL "Do not build vendored Jansson tests" FO
 set(JANSSON_EXAMPLES OFF CACHE BOOL "Do not build vendored Jansson examples" FORCE)
 set(JANSSON_BUILD_DOCS OFF CACHE BOOL "Do not build vendored Jansson docs" FORCE)
 
-add_subdirectory(deps/jansson EXCLUDE_FROM_ALL)
+# Add one vendored dependency, if nobody has already declared it and the
-add_subdirectory(deps/libakerror EXCLUDE_FROM_ALL)
+# submodule is actually checked out.
-add_subdirectory(deps/libakstdlib EXCLUDE_FROM_ALL)
+#
-add_subdirectory(deps/SDL EXCLUDE_FROM_ALL)
+# A macro rather than a function on purpose: add_subdirectory() inside a
-add_subdirectory(deps/SDL_image EXCLUDE_FROM_ALL)
+# function runs with that function's variable scope, so every cache-ish variable
-add_subdirectory(deps/SDL_mixer EXCLUDE_FROM_ALL)
+# these projects set for their own subdirectories would be discarded on return.
-add_subdirectory(deps/SDL_ttf EXCLUDE_FROM_ALL)
+macro(akgl_add_vendored_dependency target dir)
+  if(NOT TARGET ${target})
+    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${dir}/CMakeLists.txt")
+      add_subdirectory(${dir} EXCLUDE_FROM_ALL)
+      set(AKGL_VENDORED_DEPENDENCIES TRUE)
+    endif()
+  endif()
+endmacro()
+
+# Added on both paths, not just when this is the top-level project. Embedded
+# with add_subdirectory(), the submodules under deps/ are sitting right there --
+# the recursive clone the consumer just did put them there -- and refusing to
+# configure until SDL3 is installed system-wide is a failure with its own answer
+# three directories away. if(NOT TARGET ...) means a consumer that has already
+# declared one of these wins; the EXISTS check means a checkout without
+# submodules falls through to find_package below.
+akgl_add_vendored_dependency(jansson::jansson deps/jansson)
+akgl_add_vendored_dependency(akerror::akerror deps/libakerror)
+akgl_add_vendored_dependency(akstdlib::akstdlib deps/libakstdlib)
+akgl_add_vendored_dependency(SDL3::SDL3 deps/SDL)
+akgl_add_vendored_dependency(SDL3_image::SDL3_image deps/SDL_image)
+akgl_add_vendored_dependency(SDL3_mixer::SDL3_mixer deps/SDL_mixer)
+akgl_add_vendored_dependency(SDL3_ttf::SDL3_ttf deps/SDL_ttf)
 
 # libakerror 1.0.0 sizes its own status-name registry; consumers no longer do.
 # libakgl claims its status codes at runtime in akgl_heap_init() instead.
 
 set(AKGL_SUPPRESS_DEPENDENCY_TESTS FALSE)
 
-else()
+# Anything the vendored block did not supply has to come from the system.
-
+if(NOT (TARGET SDL3::SDL3 AND TARGET SDL3_image::SDL3_image AND
+        TARGET SDL3_mixer::SDL3_mixer AND TARGET SDL3_ttf::SDL3_ttf AND
+        TARGET akerror::akerror AND TARGET akstdlib::akstdlib AND
+        TARGET jansson::jansson))
+  # Only needed to locate installed copies; a fully vendored build does not
+  # require pkg-config to be present at all.
   find_package(PkgConfig REQUIRED)
+endif()
 
-  if(NOT TARGET SDL3::SDL3)
+if(NOT TARGET SDL3::SDL3)
   find_package(SDL3 REQUIRED)
-  endif()
+endif()
-  if(NOT TARGET SDL3_image::SDL3_image)
+if(NOT TARGET SDL3_image::SDL3_image)
   find_package(SDL3_image REQUIRED)
-  endif()
+endif()
-  if(NOT TARGET SDL3_mixer::SDL3_mixer)
+if(NOT TARGET SDL3_mixer::SDL3_mixer)
   find_package(SDL3_mixer REQUIRED)
-  endif()
+endif()
-  if(NOT TARGET SDL3_ttf::SDL3_ttf)
+if(NOT TARGET SDL3_ttf::SDL3_ttf)
   find_package(SDL3_ttf REQUIRED)
-  endif()
+endif()
-  # No version here: libakerror ships no akerrorConfigVersion.cmake, so asking
+# No version here: libakerror ships no akerrorConfigVersion.cmake, so asking
-  # for one makes find_package reject every install. The floor is enforced by
+# for one makes find_package reject every install. The floor is enforced by
-  # the #error in include/akgl/error.h instead, which feature-tests
+# the #error in include/akgl/error.h instead, which feature-tests
-  # AKERR_FIRST_CONSUMER_STATUS.
+# AKERR_FIRST_CONSUMER_STATUS.
-  if(NOT TARGET akerror::akerror)
+if(NOT TARGET akerror::akerror)
   find_package(akerror REQUIRED)
-  endif()
+endif()
-  # 0.2 rather than bare: libakstdlib 0.2.0 ships an akstdlibConfigVersion.cmake
+# 0.2 rather than bare: libakstdlib 0.2.0 ships an akstdlibConfigVersion.cmake
-  # with SameMinorVersion compatibility, mirroring its soname, so this accepts
+# with SameMinorVersion compatibility, mirroring its soname, so this accepts
-  # any 0.2.x and refuses 0.3 and 1.0. Unversioned, this path would silently
+# any 0.2.x and refuses 0.3 and 1.0. Unversioned, this path would silently
-  # accept an ABI-incompatible libakstdlib.
+# accept an ABI-incompatible libakstdlib.
-  if(NOT TARGET akstdlib::akstdlib)
+if(NOT TARGET akstdlib::akstdlib)
   find_package(akstdlib 0.2 REQUIRED)
-  endif()
+endif()
-  if(NOT TARGET jansson::jansson)
+if(NOT TARGET jansson::jansson)
   find_package(jansson)
-  endif()
-  
 endif()
 
 set(GAMECONTROLLERDB_H "include/akgl/SDL_GameControllerDB.h")
@@ -261,8 +287,9 @@ target_link_libraries(charviewer PRIVATE akstdlib::akstdlib akerror::akerror akg
 # project subdirectories that are not on the loader's default search path, so a
 # freshly built test aborts before main() with "cannot open shared object file".
 # Bake those directories into the build-tree RPATH. Installed builds resolve the
-# same libraries through find_package and need no help.
+# same libraries through find_package and need no help, so this keys on whether
-if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+# anything was actually vendored rather than on being the top-level project.
+if(AKGL_VENDORED_DEPENDENCIES)
   set(AKGL_VENDORED_RPATH
     "$<TARGET_FILE_DIR:SDL3::SDL3>"
     "$<TARGET_FILE_DIR:SDL3_image::SDL3_image>"