simplify guard of uClibc internals
simplify guard of uClibc internals

Simplify guard of uClibc internals, since _LIBC sections are removed on install.

Signed-off-by: Peter S. Mazinger <1f4071d9f342c1637b13af9bc258f2ff72e96758@gmx.net>

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