cmake: set TOOLCHAIN_HAS_PICOLIBC

Indicate to the build system that Zephyr SDK has full support for
Picolibc.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Author: tejlmand

cmake/zephyr/generic.cmake

@@ -30,3 +30,4 @@ endif()
 set(CROSS_COMPILE ${one_toolchain_root}/${CROSS_COMPILE_TARGET}/bin/${CROSS_COMPILE_TARGET}-)
 set(SYSROOT_DIR   ${one_toolchain_root}/${SYSROOT_TARGET}/${SYSROOT_TARGET})
 set(TOOLCHAIN_HAS_NEWLIB ON CACHE BOOL "True if toolchain supports newlib")
+set(TOOLCHAIN_HAS_PICOLIBC ON CACHE BOOL "True if toolchain supports picolibc")