rules.mak: Support .cc as a C++ source file suffix

The A64 disassembler libvixl uses .cc as its suffix for
C++ source files, so add support for it (we already support
.cpp).
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <rth@twiddle.net>

rules.mak

@@ -8,6 +8,7 @@ MAKEFLAGS += -rR
 %.d:
 %.h:
 %.c:
+%.cc:
 %.cpp:
 %.m:
 %.mak:
@@ -54,6 +55,9 @@ endif
 %.o: %.asm
 	$(call quiet-command,$(AS) $(ASFLAGS) -o $@ $<,"  AS    $(TARGET_DIR)$@")
 
+%.o: %.cc
+	$(call quiet-command,$(CXX) $(QEMU_INCLUDES) $(QEMU_CXXFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<,"  CXX   $(TARGET_DIR)$@")
+
 %.o: %.cpp
 	$(call quiet-command,$(CXX) $(QEMU_INCLUDES) $(QEMU_CXXFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<,"  CXX   $(TARGET_DIR)$@")
 
@@ -77,7 +81,7 @@ quiet-command = $(if $(V),$1,$(if $(2),@echo $2 && $1, @$1))
 cc-option = $(if $(shell $(CC) $1 $2 -S -o /dev/null -xc /dev/null \
               >/dev/null 2>&1 && echo OK), $2, $3)
 
-VPATH_SUFFIXES = %.c %.h %.S %.cpp %.m %.mak %.texi %.sh %.rc
+VPATH_SUFFIXES = %.c %.h %.S %.cc %.cpp %.m %.mak %.texi %.sh %.rc
 set-vpath = $(if $1,$(foreach PATTERN,$(VPATH_SUFFIXES),$(eval vpath $(PATTERN) $1)))
 
 # find-in-path