font-variations breaks the build on non-Freetype platforms (e.g. Quartz).
CC cairo_test_suite-font-variations.o
font-variations.c:31:10: fatal error: 'ft2build.h' file not found
#include <ft2build.h>
^~~~~~~~~~~~
1 error generated.
make[4]: *** [Makefile:4813: cairo_test_suite-font-variations.o] Error 1
test/font-variations.c requires ft2build.h, which isn't available when Cairo is built without freetype support. It also leads with a comment "/* This test requires freetype2 */". I think that makes it a freetype test that should be built only when CAIRO_HAS_FT_FONT is true.