posix: cmake: Abstract freestanding options

clang has problems compiling the native_posix with -fno-freestanding.

Signed-off-by: Oleg Zhurakivskyy <oleg.zhurakivskyy@intel.com>

arch/posix/CMakeLists.txt

@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 
 zephyr_compile_options(
-  -fno-freestanding
   -m32
   -MMD
   -MP
@@ -9,6 +8,9 @@ zephyr_compile_options(
   -include ${ZEPHYR_BASE}/arch/posix/include/posix_cheats.h
   )
 
+# @Intent: Obtain compiler specific flags for no freestanding compilation
+toolchain_cc_no_freestanding_options()
+
 zephyr_include_directories(${BOARD_DIR})
 
 zephyr_compile_options_ifdef(CONFIG_COVERAGE

cmake/compiler/clang/target.cmake

@@ -79,3 +79,8 @@ include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_baremetal.cmake)
 macro(toolchain_cc_security_fortify)
   # No op, clang doesn't understand fortify at all
 endmacro()
+
+macro(toolchain_cc_no_freestanding_options)
+  # No op, this is used by the native_posix, clang has problems
+  # compiling the native_posix with -fno-freestanding.
+endmacro()

cmake/compiler/gcc/target.cmake

@@ -131,6 +131,7 @@ list(APPEND CMAKE_REQUIRED_FLAGS -nostartfiles -nostdlib ${isystem_include_flags
 string(REPLACE ";" " " CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
 
 # Load toolchain_cc-family macros
+include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_freestanding.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_security_fortify.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_security_canaries.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_optimizations.cmake)

cmake/compiler/gcc/target_freestanding.cmake

@@ -0,0 +1,8 @@
+# Copyright (c) 2019 Intel Corporation.
+# SPDX-License-Identifier: Apache-2.0
+
+macro(toolchain_cc_no_freestanding_options)
+
+  zephyr_cc_option(-fno-freestanding)
+
+endmacro()

cmake/compiler/host-gcc/target.cmake

@@ -81,6 +81,7 @@ endforeach()
 
 # Load toolchain_cc-family macros
 # Significant overlap with freestanding gcc compiler so reuse it
+include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_freestanding.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_security_fortify.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_security_canaries.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_optimizations.cmake)