kconfig: review proposal on PR#53338

Review proposal for PR#53338.
Changes can be moved to correct commits or this commit message can be
re-written and changes used as is.

Signed-off-by: Torsten Rasmussen <[email protected]>

Author: tejlmand

lib/libc/Kconfig

@@ -19,7 +19,8 @@ config PICOLIBC_SUPPORTED
 	bool
 	depends on ARC || ARM || ARM64 || MIPS || RISCV
 	depends on "$(ZEPHYR_TOOLCHAIN_VARIANT)" != "arcmwdt"
-	depends on !CPLUSPLUS || !PICOLIBC_MODULE
+        # Picolibc with C++ support in Zephyr SDK is handled by Zephyr SDK's own Kconfig.
+        depends on !(CPLUSPLUS && "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "zephyr")
 	default y
 	help
 	  Selected when the target has support for picolibc.
@@ -43,6 +44,7 @@ config PICOLIBC
 	select THREAD_LOCAL_STORAGE if ARCH_HAS_THREAD_LOCAL_STORAGE && TOOLCHAIN_SUPPORTS_THREAD_LOCAL_STORAGE
 	select LIBC_ERRNO if THREAD_LOCAL_STORAGE
 	depends on !NATIVE_APPLICATION
+	depends on PICOLIBC_SUPPORTED
 	help
 	  Build with picolibc library. The picolibc library is built as
 	  a module if PICOLIBC_MODULE is set, otherwise picolibc is
@@ -69,12 +71,6 @@ config EXTERNAL_LIBC
 
 endchoice # LIBC_IMPLEMENTATION
 
-config PICOLIBC_MODULE
-	bool "Use picolibc module"
-	default y if !CPLUSPLUS
-	help
-	  Use picolibc module instead of picolibc included with toolchain
-
 config HAS_NEWLIB_LIBC_NANO
 	bool
 

lib/libc/picolibc/Kconfig

@@ -3,6 +3,14 @@
 
 if PICOLIBC
 
+config PICOLIBC_USE_MODULE
+	bool "Picolibc as module"
+	default y
+	depends on ZEPHYR_PICOLIBC_MODULE
+	depends on !CPLUSPLUS
+	help
+	  Use picolibc module instead of picolibc included with toolchain
+
 config PICOLIBC_HEAP_SIZE
 	int "Picolibc heap size (bytes)"
 	default 16384 if MMU
@@ -33,14 +41,7 @@ config PICOLIBC_IO_FLOAT
 	help
 	  Include floating point support in printf/scanf functions.
 
-if PICOLIBC_MODULE
-
-config PICOLIBC_USE_MODULE
-	bool
-	default y
-	help
-	  Hidden option that tells the picolibc module
-	  whether to build picolibc or to skip it.
+if PICOLIBC_USE_MODULE
 
 choice PICOLIBC_OPTIMIZATIONS
 	prompt "Optimization level"