patch 8.2.0630: "make tags" does not cover Haiku GUI file

Problem:    "make tags" does not cover Haiku GUI file.
Solution:   Add *.cc files.
diff --git a/src/Make_all.mak b/src/Make_all.mak
index 591350f..6a6d2fe 100644
--- a/src/Make_all.mak
+++ b/src/Make_all.mak
@@ -5,6 +5,7 @@
 # Argument for running ctags.
 TAGS_FILES = \
 	*.c \
+	*.cc \
 	*.cpp \
 	*.h \
 	auto/*.c \