Minor Makefile simplifications for lib/atf/...

- Replace uses of `${.CURDIR:H:H:H}` with ${SRCTOP}
- Use built-in :H operator instead of ".." when enumerating paths.

MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division

lib/atf/libatf-c++/Makefile

@@ -35,15 +35,15 @@ SHLIB_MAJOR=	2
 # libatf-c++ depends on the C version of the ATF library to build.
 LIBADD+=	atf_c
 
-LDFLAGS+=	-L${.OBJDIR}/../libatf-c
+LDFLAGS+=	-L${.OBJDIR:H}/libatf-c
 
-ATF=		${.CURDIR:H:H:H}/contrib/atf
+ATF=		${SRCTOP}/contrib/atf
 .PATH:		${ATF}
 .PATH:		${ATF}/atf-c++
 .PATH:		${ATF}/atf-c++/detail
 
 CFLAGS+=	-I${ATF}
-CFLAGS+=	-I${.CURDIR}/../libatf-c
+CFLAGS+=	-I${.CURDIR:H}/libatf-c
 CFLAGS+=	-I.
 
 CFLAGS+=	-DHAVE_CONFIG_H

lib/atf/libatf-c/Makefile

@@ -36,7 +36,7 @@ LIB=		atf-c
 PRIVATELIB=	true
 SHLIB_MAJOR=	1
 
-ATF=		${.CURDIR:H:H:H}/contrib/atf
+ATF=		${SRCTOP}/contrib/atf
 .PATH:		${ATF}
 .PATH:		${ATF}/atf-c
 .PATH:		${ATF}/atf-c/detail