The check was actually half-broken from the beginning and
until df83ee4; the thick red line was rendered properly but
the error text was rendered with width 0, which by chance worked
on some GL implementations. That commit has fixed the underlying
bug but left the text line width at 0 to avoid test breakage.
This commit fixes the bug, turns off the check completely, and
updates the tests to account for breakage.
This commit alters the build system substantially; it adds another
platform, `headless`, that provides stubs in place of all GUI
functions, and provides a library `solvespace_headless` alongside
the main executable. To cut down build times, only the few files
that have #if defined(HEADLESS) are built twice for the executable
and the library; the rest is grouped into a new `solvespace_cad`
library. It is not usable on its own and just serves for grouping.
This commit also gates the tests behind a -DENABLE_TESTS=ON CMake
option, ON by default (but suggested as OFF in the README so that
people don't ever have to install cairo to build the executable.)
The tests introduced in this commit are (so far) rudimentary,
although functional, and they serve as a stepping point towards
introducing coverage analysis.
whitequark