Index: Makefile
===================================================================
--- Makefile
+++ Makefile
@@ -445,6 +445,9 @@
 .endif
 KERNSRCDIR?=		${.CURDIR}/sys
 
+# Directory for writing logs etc
+UNIVERSE_LOGDIR?=${.CURDIR}
+
 targets:	.PHONY
 	@echo "Supported TARGET/TARGET_ARCH pairs for world and kernel targets"
 .for target in ${TARGETS}
@@ -454,7 +457,7 @@
 .endfor
 
 .if defined(DOING_TINDERBOX)
-FAILFILE=${.CURDIR}/_.tinderbox.failed
+FAILFILE=${UNIVERSE_LOGDIR}/_.tinderbox.failed
 MAKEFAIL=tee -a ${FAILFILE}
 .else
 MAKEFAIL=cat
@@ -487,9 +490,9 @@
 	    ${SUB_MAKE} ${JFLAG} ${UNIVERSE_TARGET} \
 	    TARGET=${target} \
 	    TARGET_ARCH=${target_arch} \
-	    > _.${target}.${target_arch}.${UNIVERSE_TARGET} 2>&1 || \
+	    > ${UNIVERSE_LOGDIR}/_.${target}.${target_arch}.${UNIVERSE_TARGET} 2>&1 || \
 	    (echo "${target}.${target_arch} ${UNIVERSE_TARGET} failed," \
-	    "check _.${target}.${target_arch}.${UNIVERSE_TARGET} for details" | \
+	    "check ${UNIVERSE_LOGDIR}/_.${target}.${target_arch}.${UNIVERSE_TARGET} for details" | \
 	    ${MAKEFAIL}))
 	@echo ">> ${target}.${target_arch} ${UNIVERSE_TARGET} completed on `LC_ALL=C date`"
 .endfor
@@ -501,9 +504,9 @@
 universe_${target}_kernels: universe_${target}_prologue .MAKE .PHONY
 .if exists(${KERNSRCDIR}/${target}/conf/NOTES)
 	@(cd ${KERNSRCDIR}/${target}/conf && env __MAKE_CONF=/dev/null \
-	    ${SUB_MAKE} LINT > ${.CURDIR}/_.${target}.makeLINT 2>&1 || \
+	    ${SUB_MAKE} LINT > ${UNIVERSE_LOGDIR}/_.${target}.makeLINT 2>&1 || \
 	    (echo "${target} 'make LINT' failed," \
-	    "check _.${target}.makeLINT for details"| ${MAKEFAIL}))
+	    "check ${UNIVERSE_LOGDIR}/_.${target}.makeLINT for details"| ${MAKEFAIL}))
 .endif
 	@cd ${.CURDIR}; ${SUB_MAKE} ${.MAKEFLAGS} TARGET=${target} \
 	    universe_kernels
@@ -543,9 +546,9 @@
 	    TARGET=${TARGET} \
 	    TARGET_ARCH=${TARGET_ARCH_${kernel}} \
 	    KERNCONF=${kernel} \
-	    > _.${TARGET}.${kernel} 2>&1 || \
+	    > ${UNIVERSE_LOGDIR}/_.${TARGET}.${kernel} 2>&1 || \
 	    (echo "${TARGET} ${kernel} kernel failed," \
-	    "check _.${TARGET}.${kernel} for details"| ${MAKEFAIL}))
+	    "check ${UNIVERSE_LOGDIR}/_.${TARGET}.${kernel} for details"| ${MAKEFAIL}))
 .endfor
 universe: universe_epilogue
 universe_epilogue: .PHONY
Index: share/man/man7/build.7
===================================================================
--- share/man/man7/build.7
+++ share/man/man7/build.7
@@ -639,6 +639,11 @@
 invocation used to build worlds and kernels.
 This can be used to enable multiple jobs within a single architecture's build
 while still building each architecture serially.
+.It Va UNIVERSE_LOGDIR
+By default, logfiles for each target are saved it the root of the src tree
+(normally
+.Pa /usr/src ).
+This option specifies an alternate directory for these logfiles.
 .It Va MAKE_JUST_KERNELS
 Only build kernels for each supported architecture.
 .It Va MAKE_JUST_WORLDS