This morning I changed one header and watched the old build machinery reconsider what appeared to be western civilisation. That was enough encouragement to try the same small library with CMake.

The useful bit was not clever syntax. It was stating the target directly:

set(parser_SRCS parser.cpp token.cpp)
kde4_add_library(parser ${parser_SRCS})
target_link_libraries(parser ${QT_QTCORE_LIBRARY})
install(TARGETS parser DESTINATION ${LIB_INSTALL_DIR})

I configured outside the source tree:

mkdir build
cd build
cmake ..
make VERBOSE=1

That last command matters while converting. The generated command line tells me which include path, definition, or library I forgot. Guessing from a linker error is possible, but so is repairing a watch with a spoon.

I prefer one explicit target with its own sources and libraries over directory-wide flags. It makes dependencies visible and avoids accidentally linking every library against everything else. The caveat is that our CMake helper macros are still moving, so a tidy file today may need adjustment next week.

My practical rule is to convert one buildable directory at a time, compile it, then continue. A giant mechanical conversion produces a giant pile of errors with no useful ordering. Small green steps are less heroic and considerably faster.