fix building when pthread support is disabled
fix building when pthread support is disabled

wbx-github/uclibc-ng,klee/klee-uclibc,klee/klee-uclibc,atgreen/uClibc-moxie,brgl/uclibc-ng,ysat0/uClibc,ffainelli/uClibc,ddcc/klee-uclibc-0.9.33.2,atgreen/uClibc-moxie,foss-for-synopsys-dwc-arc-processors/uClibc,brgl/uclibc-ng,kraj/uclibc-ng,ndmsystems/uClibc,hjl-tools/uClibc,m-labs/uclibc-lm32,groundwater/uClibc,ChickenRunjyd/klee-uclibc,ysat0/uClibc,waweber/uclibc-clang,foss-for-synopsys-dwc-arc-processors/uClibc,klee/klee-uclibc,waweber/uclibc-clang,ndmsystems/uClibc,mephi42/uClibc,foss-xtensa/uClibc,kraj/uClibc,hwoarang/uClibc,czankel/xtensa-uclibc,atgreen/uClibc-moxie,hwoarang/uClibc,ffainelli/uClibc,gittup/uClibc,majek/uclibc-vx32,OpenInkpot-archive/iplinux-uclibc,OpenInkpot-archive/iplinux-uclibc,gittup/uClibc,hjl-tools/uClibc,klee/klee-uclibc,OpenInkpot-archive/iplinux-uclibc,skristiansson/uClibc-or1k,ffainelli/uClibc,kraj/uClibc,czankel/xtensa-uclibc,m-labs/uclibc-lm32,ysat0/uClibc,skristiansson/uClibc-or1k,czankel/xtensa-uclibc,ffainelli/uClibc,OpenInkpot-archive/iplinux-uclibc,groundwater/uClibc,wbx-github/uclibc-ng,m-labs/uclibc-lm32,majek/uclibc-vx32,wbx-github/uclibc-ng,czankel/xtensa-uclibc,kraj/uClibc,kraj/uclibc-ng,hjl-tools/uClibc,ChickenRunjyd/klee-uclibc,mephi42/uClibc,kraj/uclibc-ng,hwoarang/uClibc,ChickenRunjyd/klee-uclibc,ndmsystems/uClibc,groundwater/uClibc,ddcc/klee-uclibc-0.9.33.2,mephi42/uClibc,skristiansson/uClibc-or1k,wbx-github/uclibc-ng,majek/uclibc-vx32,ddcc/klee-uclibc-0.9.33.2,kraj/uclibc-ng,hjl-tools/uClibc,ffainelli/uClibc,ysat0/uClibc,majek/uclibc-vx32,ndmsystems/uClibc,hwoarang/uClibc,brgl/uclibc-ng,foss-xtensa/uClibc,ChickenRunjyd/klee-uclibc,mephi42/uClibc,groundwater/uClibc,hjl-tools/uClibc,foss-xtensa/uClibc,gittup/uClibc,brgl/uclibc-ng,skristiansson/uClibc-or1k,m-labs/uclibc-lm32,kraj/uClibc,waweber/uclibc-clang,foss-xtensa/uClibc,gittup/uClibc,groundwater/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,ddcc/klee-uclibc-0.9.33.2,atgreen/uClibc-moxie,waweber/uclibc-clang