add math library openlibm support (1)open menuconfig (2)close math.h:build setup->Customize Header Files->math.h (3) select openlibm:Library Rountines->Select math library->Math Library fram openlibm (4)build Signed-off-by: yanghuatao <yanghuatao@xiaomi.com>
Signed-off-by: yanghuatao <yanghuatao@xiaomi.com>
to prepare the support of other implementation e.g.: https://github.com/JuliaMath/openlibm https://gitlab.com/gtd-gmbh/libmcs Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>