patch 8.2.2928: the evalfunc.c file is too big

Problem:    The evalfunc.c file is too big.
Solution:   Move float related functionality to a separate file. (Yegappan
            Lakshmanan, closes #8287)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 0be3abb..c33200b 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -749,6 +749,7 @@
 	$(OUTDIR)/fileio.o \
 	$(OUTDIR)/filepath.o \
 	$(OUTDIR)/findfile.o \
+	$(OUTDIR)/float.o \
 	$(OUTDIR)/fold.o \
 	$(OUTDIR)/getchar.o \
 	$(OUTDIR)/gui_xim.o \