diff '--color=auto' -u -r fltk-1.3.11.org/src/Makefile fltk-1.3.11/src/Makefile
--- fltk-1.3.11.org/src/Makefile	2025-12-28 23:11:47.256650869 +0900
+++ fltk-1.3.11/src/Makefile	2025-12-28 23:18:56.006688919 +0900
@@ -219,7 +219,7 @@
 
 MMFILES = $(shell if test $(USEMMFILES) = Yes; then echo $(OBJCPPFILES); fi)
 
-OBJECTS =  $(MMFILES:.mm=.o) $(CPPFILES:.cxx=.o) $(CFILES:.c=.o) $(UTF8CFILES:.c=.o)
+OBJECTS =  $(MMFILES:.mm=.o) $(CPPFILES:.cxx=.o) $(CFILES:.c=.o) $(UTF8CFILES:.c=.o) ../cairo/Fl_Cairo.o
 GLOBJECTS = $(GLCPPFILES:.cxx=.o)
 FLOBJECTS = $(FLCPPFILES:.cxx=.o)
 IMGOBJECTS = $(IMGCPPFILES:.cxx=.o)