rt-tests do_compile failed occasionally when PARALLEL_MAKE is set with a high number:e.g. PARALLEL_MAKE = "-j 19":

| mips-poky-linux-gcc  -meb -mabi=32   -mhard-float -march=mips32 --sysroot=/buildarea1/jhuang0/yocto/y_mips_1114/tmp/sysroots/qemumips -D VERSION_STRING=0.85 -c src/hackbench/hackbench.c -O2 -pipe -g -feliminate-unused-debug-types -I/buildarea1/jhuang0/yocto/y_mips_1114/tmp/work/mips32-poky-linux/rt-tests/0.85-r0.0/git/src/include -D_GNU_SOURCE -Wall -Wno-nonnulli -O2  -D_GNU_SOURCE -Isrc/include
| src/signaltest/signaltest.c: In function 'signalthread':
| src/signaltest/signaltest.c:130:27: warning: null argument where non-null required (argument 1) [-Wnonnull]
| src/signaltest/signaltest.c:176:5: warning: null argument where non-null required (argument 1) [-Wnonnull]
| src/cyclictest/cyclictest.c: In function 'tracing':
| src/cyclictest/cyclictest.c:407:43: warning: null argument where non-null required (argument 1) [-Wnonnull]
| src/cyclictest/cyclictest.c:417:3: warning: null argument where non-null required (argument 1) [-Wnonnull]
| chmod +x src/hwlatdetect/hwlatdetect.py
| ln -s src/hwlatdetect/hwlatdetect.py hwlatdetect
| src/signaltest/signaltest.c: At top level:
| cc1: warning: unrecognized command line option "-Wno-nonnulli" [enabled by default]
| mips-poky-linux-gcc  -meb -mabi=32   -mhard-float -march=mips32 --sysroot=/buildarea1/jhuang0/yocto/y_mips_1114/tmp/sysroots/qemumips -O2 -pipe -g -feliminate-unused-debug-types -I/buildarea1/jhuang0/yocto/y_mips_1114/tmp/work/mips32-poky-linux/rt-tests/0.85-r0.0/git/src/include -D_GNU_SOURCE -Wall -Wno-nonnulli -O2 -Wl,-O1  -Wl,--as-needed -o hackbench hackbench.o -lrt -lpthread -lrttest -L.
| /buildarea1/jhuang0/yocto/y_mips_1114/tmp/sysroots/x86_64-linux/usr/libexec/mips32-poky-linux/gcc/mips-poky-linux/4.7.2/ld: cannot find -lrttest
| collect2: error: ld returned 1 exit status
| make: *** [hackbench] Error 1
| make: *** Waiting for unfinished jobs....
| src/cyclictest/cyclictest.c: At top level:
| cc1: warning: unrecognized command line option "-Wno-nonnulli" [enabled by default]
| mips-poky-linux-ar rcs librttest.a rt-utils.o error.o rt-get_cpu.o
| ERROR: oe_runmake failed
| ERROR: Function failed: do_compile (see /buildarea1/jhuang0/yocto/y_mips_1114/tmp/work/mips32-poky-linux/rt-tests/0.85-r0.0/temp/log.do_compile.6680 for further information)
NOTE: recipe rt-tests-0.85-r0.0: task do_compile: Failed
ERROR: Task 6 (/buildarea1/jhuang0/git/poky/meta/recipes-rt/rt-tests/rt-tests_0.85.bb, do_compile) failed with exit code '1'
NOTE: Tasks Summary: Attempted 480 tasks of which 474 didn't need to be rerun and 1 failed.

Summary: 1 task failed:
  /buildarea1/jhuang0/git/poky/meta/recipes-rt/rt-tests/rt-tests_0.85.bb, do_compile
Summary: There was 1 WARNING message shown.
Summary: There was 1 ERROR message shown, returning a non-zero exit code.