config: Split debug build from debug symbols

RPM based packaging systems expect binaries to have debug symbols which get
placed in a separate debuginfo RPM.

Split the concept of a debug build up so that binaries can be built with
debugging symbols without having the other gubbins which $(debug) implies, most
notibly frame pointers.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

Config.mk

@@ -11,6 +11,7 @@ realpath = $(wildcard $(foreach file,$(1),$(shell cd -P $(dir $(file)) && echo "
 
 # A debug build of Xen and tools?
 debug ?= y
+debug_symbols ?= $(debug)
 
 XEN_COMPILE_ARCH    ?= $(shell uname -m | sed -e s/i.86/x86_32/ \
                          -e s/i86pc/x86_32/ -e s/amd64/x86_64/ -e s/arm.*/arm/)
@@ -147,7 +148,7 @@ define buildmakevars2file-closure
 	$(call move-if-changed,$(1).tmp,$(1))
 endef
 
-ifeq ($(debug),y)
+ifeq ($(debug_symbols),y)
 CFLAGS += -g
 endif