libc/newlib: allow using newlib with archs other than avr32

config/libc.in

@@ -4,8 +4,6 @@ menu "C-library"
 
 config LIBC
     string
-    default "newlib" if BARE_METAL && ARCH_avr32 && EXPERIMENTAL
-    default "none" if BARE_METAL
 
 config LIBC_VERSION
     string
@@ -23,8 +21,6 @@ config LIBC_VERSION
 
 source config.gen/libc.in
 
-comment "Common C library options"
-
 config LIBC_SUPPORT_NPTL
     bool
     default n
@@ -37,7 +33,12 @@ config THREADS
     string
     default "nptl"          if THREADS_NPTL
     default "linuxthreads"  if THREADS_LINUXTHREADS
-    default "none"          if THREADS_NONE
+    default "none"          if THREADS_NONE || LIBC_none
+#                              No C library, no threads!
+
+if ! LIBC_none
+
+comment "Common C library options"
 
 choice
     bool
@@ -62,4 +63,6 @@ config THREADS_NONE
 
 endchoice
 
+endif # ! LIBC_none
+
 endmenu

config/libc/newlib.in

@@ -1,14 +1,14 @@
 # newlib options
-# depends on EXPERIMENTAL
+# depends on EXPERIMENTAL && BARE_METAL
 
 config LIBC_newlib
     help
-    Newlib is a C library intended for use on embedded systems. It is a 
+      Newlib is a C library intended for use on embedded systems. It is a
-    conglomeration of several library parts, all under free software 
+      conglomeration of several library parts, all under free software
-    licenses that make them easily usable on embedded products. Newlib 
+      licenses that make them easily usable on embedded products. Newlib
-    is only available in source form. It can be compiled for a wide 
+      is only available in source form. It can be compiled for a wide
-    array of processors, and will usually work on any architecture with
+      array of processors, and will usually work on any architecture with
-    the addition of a few low-level routines. 
+      the addition of a few low-level routines.
 
 choice
     bool
@@ -31,10 +31,10 @@ config LIBC_VERSION
 config ATMEL_AVR32_HEADERS
     bool
     prompt "Install Atmel AVR32 headers"
+    depends on ARCH_avr32
     default y
     help
       Install Atmel AVR32 headers for native AVR32 development. Most
       AVR32 MCU devices are supported.
       
       If you do native AVR32 development you want to say 'Y' here.
-

config/libc/none.in

@@ -0,0 +1,14 @@
+# Dummy config file to not use a C library *at all*
+# depends on BARE_METAL
+
+config LIBC_none
+    help
+      Do not use a C library.
+      
+      This is usefull if your project is self-contained, does not rely on
+      an external C library, and provides all the necessary bits.
+      
+      Most probably usefull to bootloaders, as they generally don't depend
+      on the C library.
+      
+      If unsure: do *not* choose that, and use another option in the choice.

scripts/build/arch/arm.sh

@@ -8,7 +8,7 @@ CT_DoArchTupleValues() {
     case "${CT_LIBC},${CT_ARCH_ARM_EABI}" in
         *glibc,y)   CT_TARGET_SYS=gnueabi;;
         uClibc,y)   CT_TARGET_SYS=uclibcgnueabi;;
-        none,y)     CT_TARGET_SYS=eabi;;
+        *,y)        CT_TARGET_SYS=eabi;;
     esac
 
     # In case we're EABI, do *not* specify any ABI!

scripts/functions

@@ -696,9 +696,9 @@ CT_DoBuildTargetTuple() {
     # Set defaults for the system part of the tuple. Can be overriden
     # by architecture-specific values.
     case "${CT_LIBC}" in
-        none)   CT_TARGET_SYS=elf;;
         *glibc) CT_TARGET_SYS=gnu;;
         uClibc) CT_TARGET_SYS=uclibc;;
+        *)      CT_TARGET_SYS=elf;;
     esac
 
     # Transform the ARCH into a kernel-understandable ARCH