libc/Kconfig: Break big Kconfig up into separate Kconfig files in each libc subdirectory.

libc/string/Kconfig

@@ -0,0 +1,89 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "errno Decode Support"
+
+config LIBC_STRERROR
+	bool "Enable strerror"
+	default n
+	---help---
+		strerror() is useful because it decodes 'errno' values into a human readable
+		strings.  But it can also require a lot of memory.  If this option is selected,
+		strerror() will still exist in the build but it will not decode error values.
+		This option should be used by other logic to decide if it should use strerror()
+		or not.  For example, the NSH application will not use strerror() if this
+		option is not selected; perror() will not use strerror() is this option is not
+		selected (see also NSH_STRERROR).
+
+config LIBC_STRERROR_SHORT
+	bool "Use short error descriptions in strerror()"
+	default n
+	depends on LIBC_STRERROR
+	---help---
+		If this option is selected, then strerror() will use a shortened string when
+		it decodes the error.  Specifically, strerror() is simply use the string that
+		is the common name for the error.  For example, the 'errno' value of 2 will
+		produce the string "No such file or directory" is LIBC_STRERROR_SHORT
+		is not defined but the string "ENOENT" is LIBC_STRERROR_SHORT is defined.
+
+config LIBC_PERROR_STDOUT
+	bool "perror() to stdout"
+	default n
+	---help---
+		POSIX requires that perror() provide its output on stderr.  This option may
+		be defined, however, to provide perror() output that is serialized with
+		other stdout messages.
+
+comment "memcpy/memset Options"
+
+config MEMCPY_VIK
+	bool "Vik memcpy()"
+	default n
+	depends on !LIBC_ARCH_MEMCPY
+	---help---
+		Select this option to use the optimized memcpy() function by Daniel Vik.
+		Select this option for improved performance at the expense of increased
+		size. See licensing information in the top-level COPYING file.
+
+if MEMCPY_VIK
+
+config MEMCPY_PRE_INC_PTRS
+	bool "Pre-increment pointers"
+	default n
+	---help---
+		Use pre-increment of pointers. Default is post increment of pointers.
+
+config MEMCPY_INDEXED_COPY
+	bool "Array indexing"
+	default y
+	---help---
+		Copying data using array indexing. Using this option, disables the
+		MEMCPY_PRE_INC_PTRS option.
+
+config MEMCPY_64BIT
+	bool "64-bit memcpy()"
+	default n
+	---help---
+		Compiles memcpy() for architectures that suppport 64-bit operations
+		efficiently.
+
+endif # MEMCPY_VIK
+
+config MEMSET_OPTSPEED
+	bool "Optimize memset() for speed"
+	default n
+	depends on !LIBC_ARCH_MEMSET
+	---help---
+		Select this option to use a version of memcpy() optimized for speed.
+		Default: memcpy() is optimized for size.
+
+config MEMSET_64BIT
+	bool "64-bit memset()"
+	default n
+	depends on MEMSET_OPTSPEED
+	---help---
+		Compiles memset() for architectures that suppport 64-bit operations
+		efficiently.
+