toolchain: arcmwdt: don't set STDC_LIB_EXT1 macro in case of minimal libc

Don't provide __STDC_LIB_EXT1__ macro (Extensions to the C Library,
Part 1: Bounds-checking interfaces) if we use minimal libc - as we don't
have functions from this extension implemented in minimal libc.

Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>

cmake/compiler/arcmwdt/compiler_flags.cmake

@@ -116,7 +116,7 @@ set_compiler_property(PROPERTY warning_error_misra_sane -Werror=vla)
 set_compiler_property(PROPERTY cstd -std=)
 
 if (NOT CONFIG_ARCMWDT_LIBC)
-  set_compiler_property(PROPERTY nostdinc -Hno_default_include -Hnoarcexlib)
+  set_compiler_property(PROPERTY nostdinc -Hno_default_include -Hnoarcexlib -U__STDC_LIB_EXT1__)
   set_compiler_property(APPEND PROPERTY nostdinc_include ${NOSTDINC})
 endif()