libc: Added Kconfig choice to select C library

Added Kconfig choice to select C library implementation

Signed-off-by: Jan Van Winkel <jan.van_winkel@dxplore.eu>

lib/CMakeLists.txt

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 
-if(NOT CONFIG_NATIVE_APPLICATION)
+if(NOT CONFIG_EXTERNAL_LIBC)
 add_subdirectory(libc)
 add_subdirectory(posix)
 endif()

lib/libc/Kconfig

@@ -7,18 +7,44 @@
 #
 
 menu "C Library"
-depends on !NATIVE_APPLICATION
+
+config REQUIRES_FULL_LIBC
+	bool
+	help
+	  Helper symbol to indicate some feature requires a C library implementation
+	  with more functionality than what MINIMAL_LIBC provides
+
+choice LIBC_IMPLEMENTATION
+	prompt "C Library Implementation"
+	default EXTERNAL_LIBC if NATIVE_APPLICATION
+	default NEWLIB_LIBC if REQUIRES_FULL_LIBC
+	default MINIMAL_LIBC
+
+config MINIMAL_LIBC
+	bool "Minimal C library"
+	depends on !NATIVE_APPLICATION
+	help
+	  Build with minimal C library.
 
 config NEWLIB_LIBC
-	bool "Build with newlib c library"
+	bool "Newlib C library"
+	depends on !NATIVE_APPLICATION
 	help
 	  Build with newlib library. The newlib library is expected to be
 	  part of the SDK in this case.
 
+config EXTERNAL_LIBC
+	bool "External C library"
+	help
+	  Build with external/user provided C library.
+
+endchoice #LIBC_IMPLEMENTATION
+
+if NEWLIB_LIBC
+
 if "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "gnuarmemb"
 config NEWLIB_LIBC_NANO
-	bool "Build with newlib-nano c library"
-	depends on NEWLIB_LIBC
+	bool "Build with newlib-nano C library"
 	default y
 	help
 	  Build with newlib-nano library, for small embedded apps.
@@ -29,7 +55,6 @@ endif
 config NEWLIB_LIBC_ALIGNED_HEAP_SIZE
 	int "Newlib aligned heap size"
 	depends on MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT
-	depends on NEWLIB_LIBC
 	depends on USERSPACE
 	default 0
 	help
@@ -43,32 +68,22 @@ config NEWLIB_LIBC_ALIGNED_HEAP_SIZE
 
 config NEWLIB_LIBC_FLOAT_PRINTF
 	bool "Build with newlib float printf"
-	depends on NEWLIB_LIBC
 	help
 	  Build with floating point printf enabled. This will increase the size of
 	  the image.
 
 config NEWLIB_LIBC_FLOAT_SCANF
 	bool "Build with newlib float scanf"
-	depends on NEWLIB_LIBC
 	help
 	  Build with floating point scanf enabled. This will increase the size of
 	  the image.
 
-config STDOUT_CONSOLE
-	bool "Send stdout to console"
-	depends on CONSOLE_HAS_DRIVER
-	default y
-	help
-	  This option directs standard output (e.g. printf) to the console
-	  device, rather than suppressing it entirely. See also EARLY_CONSOLE
-	  option.
+endif #NEWLIB_LIBC
 
-# Minimal libc options
+if MINIMAL_LIBC
 
 config MINIMAL_LIBC_MALLOC_ARENA_SIZE
 	int "Size of the minimal libc malloc arena"
-	depends on !NEWLIB_LIBC
 	default 0
 	help
 	  Indicate the size of the memory arena used for minimal libc's
@@ -77,10 +92,21 @@ config MINIMAL_LIBC_MALLOC_ARENA_SIZE
 
 config MINIMAL_LIBC_LL_PRINTF
 	bool "Build with minimal libc long long printf" if !64BIT
-	depends on !NEWLIB_LIBC
 	default y if 64BIT
 	help
 	  Build with long long printf enabled. This will increase the size of
 	  the image.
 
+endif #MINIMAL_LIBC
+
+config STDOUT_CONSOLE
+	bool "Send stdout to console"
+	depends on CONSOLE_HAS_DRIVER
+	depends on !NATIVE_APPLICATION
+	default y
+	help
+	  This option directs standard output (e.g. printf) to the console
+	  device, rather than suppressing it entirely. See also EARLY_CONSOLE
+	  option.
+
 endmenu