Xen 4.1: Query rpm to find build directories.

Allows user with ~/.rpmmacros to build e.g.
$ cat ~/.rpmmacros
%_topdir        /data/rpmbuild
%_tmppath       /data/tmp

Signed-off-by: Ian Campbell <[email protected]>
Signed-off-by: Zheng Li <[email protected]>

Author: zli

Makefile

@@ -7,9 +7,9 @@ MY_OUTPUT_DIR ?= $(CURDIR)/output
 MY_OBJ_DIR ?= $(CURDIR)/obj
 REPO ?= $(CURDIR)
 
-RPM_SPECSDIR?=/usr/src/redhat/SPECS
-RPM_SRPMSDIR?=/usr/src/redhat/SRPMS
-RPM_SOURCESDIR?=/usr/src/redhat/SOURCES
+RPM_SPECSDIR?=$(shell rpm --eval='%_specdir')
+RPM_SRPMSDIR?=$(shell rpm --eval='%_srcrpmdir')
+RPM_SOURCESDIR?=$(shell rpm --eval='%_sourcedir')
 RPMBUILD?=rpmbuild
 XEN_RELEASE?=unknown
 endif