diff --git a/lib/libthr/Makefile b/lib/libthr/Makefile
index 517a30f21ee8..5b3e3bff71bc 100644
--- a/lib/libthr/Makefile
+++ b/lib/libthr/Makefile
@@ -18,13 +18,13 @@ LIB=thr
 SHLIB_MAJOR= 3
 WARNS?=	3
 CFLAGS+=-DPTHREAD_KERNEL
-CFLAGS+=-I${.CURDIR}/../libc/include -I${.CURDIR}/thread \
-	-I${.CURDIR}/../../include
+CFLAGS+=-I${SRCTOP}/lib/libc/include -I${.CURDIR}/thread \
+	-I${SRCTOP}/include
 CFLAGS+=-I${.CURDIR}/arch/${MACHINE_CPUARCH}/include
 CFLAGS+=-I${.CURDIR}/sys
-CFLAGS+=-I${.CURDIR}/../../libexec/rtld-elf
-CFLAGS+=-I${.CURDIR}/../../libexec/rtld-elf/${MACHINE_CPUARCH}
-CFLAGS+=-I${.CURDIR}/../libthread_db
+CFLAGS+=-I${SRCTOP}/libexec/rtld-elf
+CFLAGS+=-I${SRCTOP}/libexec/rtld-elf/${MACHINE_CPUARCH}
+CFLAGS+=-I${SRCTOP}/lib/libthread_db
 CFLAGS+=-Winline
 
 .ifndef NO_THREAD_UNWIND_STACK
@@ -34,7 +34,7 @@ CFLAGS+=-D_PTHREAD_FORCED_UNWIND
 
 LDFLAGS+=-Wl,-znodelete
 
-VERSION_DEF=${.CURDIR}/../libc/Versions.def
+VERSION_DEF=${SRCTOP}/lib/libc/Versions.def
 SYMBOL_MAPS=${.CURDIR}/pthread.map
 
 MAN=	libthr.3
diff --git a/lib/libthr/support/Makefile.inc b/lib/libthr/support/Makefile.inc
index 1814f8a5f3da..cd4d206e5ad3 100644
--- a/lib/libthr/support/Makefile.inc
+++ b/lib/libthr/support/Makefile.inc
@@ -1,15 +1,15 @@
 # $FreeBSD$
 
-.PATH: ${.CURDIR}/support ${.CURDIR}/../libc/gen ${.CURDIR}/../libc/string
+.PATH: ${.CURDIR}/support ${SRCTOP}/lib/libc/gen ${SRCTOP}/lib/libc/string
 
 # libc must search machine_arch, then machine_cpuarch, but libthr has all its
 # code implemented in machine_cpuarch.  Cope.
-.if exists(${.CURDIR}/../libc/${MACHINE_ARCH}/sys)
-.PATH: ${.CURDIR}/../libc/${MACHINE_ARCH}/sys
-CFLAGS+= -I${.CURDIR}/../libc/${MACHINE_ARCH}
+.if exists(${SRCTOP}/lib/libc/${MACHINE_ARCH}/sys)
+.PATH: ${SRCTOP}/lib/libc/${MACHINE_ARCH}/sys
+CFLAGS+= -I${SRCTOP}/lib/libc/${MACHINE_ARCH}
 .else
-.PATH: ${.CURDIR}/../libc/${MACHINE_CPUARCH}/sys
-CFLAGS+= -I${.CURDIR}/../libc/${MACHINE_CPUARCH}
+.PATH: ${SRCTOP}/lib/libc/${MACHINE_CPUARCH}/sys
+CFLAGS+= -I${SRCTOP}/lib/libc/${MACHINE_CPUARCH}
 .endif
 
 SYSCALLS= thr_new