First step of breaking up the monolithic root CMakeLists.txt: move the
add_library(Common STATIC ...) target definition, and every scattered
target_link_libraries/target_compile_definitions/target_include_directories
call touching it, into Common/CMakeLists.txt, pulled in via
add_subdirectory(Common).
Source paths are now relative to Common/ instead of prefixed with
"Common/". The two files living outside that directory (ext/jpge/*)
use ${CMAKE_SOURCE_DIR}/... instead.
include_directories(Common) stays in the root file rather than moving
into Common/CMakeLists.txt: it's a directory-scope command that needs
to affect targets defined *later* in the root file, and add_subdirectory
scope doesn't propagate upward or sideways, so moving it would have
silently broken unprefixed #includes elsewhere in the project.
add_subdirectory(Common) is placed at the point where the *last*
prerequisite variable it needs (PNG_LIBRARIES, RT_LIB, ATOMIC_LIB, etc.)
is guaranteed already set, not where the old add_library(Common ...)
used to start - some of those are resolved later in the file than
Common's original position was.
Verified with a clean ./b.sh --debug rebuild and a HEADLESS=ON
UNITTEST=ON reconfigure/build.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSNaZnHCjmryS3ziVN9gZU
