libc: libces are responsible for naming their threads implementation

This will help add new implementations, such as the one in musl.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Bryan Hundven <bryanhundven@gmail.com>

config/libc.in

@@ -39,13 +39,10 @@ config LIBC_SUPPORT_THREADS_WIN32
 config LIBC_SUPPORT_THREADS_NONE
     bool
 
+# C libraries should provide other values
 config THREADS
     string
-    default "nptl"          if THREADS_NATIVE
-    default "linuxthreads"  if THREADS_LT
-    default "win32"         if THREADS_WIN32
-    default "none"          if THREADS_NONE || LIBC_none
-#                              No C library, no threads!
+    default "none" if THREADS_NONE
 
 if ! LIBC_none
 

config/libc/eglibc.in

@@ -12,6 +12,9 @@
 ## help cross-compilation support.  EGLIBC also includes some embedded ports
 ## help (such as e500/spe) that are normally separate add-ons of GLIBC.
 
+config THREADS
+    default "nptl"
+
 choice
     bool
     prompt "eglibc version"

config/libc/glibc.in

@@ -8,6 +8,9 @@
 ## help The de-facto standard for Linux distributions.
 ## help Feature-rich, but large...  Most usefull for desktop-like systems.
 
+config THREADS
+    default "nptl"
+
 choice
     bool
     prompt "glibc version"

config/libc/mingw.in

@@ -7,6 +7,9 @@
 ##
 ## help The de-facto standard for Mingw distributions.
 
+config THREADS
+    default "win32"
+
 choice
     bool
     prompt "Windows API version"

config/libc/none.in

@@ -11,3 +11,9 @@
 ## help on the C library.
 ## help
 ## help If unsure: do *not* choose that, and use another option in the choice.
+
+# The no-threads is usually set in the main libc.in config file.
+# But since the "none" C library does not show the threads choice,
+# we have to define the no-threads value ourselves here:
+config THREADS
+    default "none"

config/libc/uClibc.in

@@ -11,6 +11,10 @@
 ## help Highly configurable, thus as feature-rich as you
 ## help need, without compromising for size.
 
+config THREADS
+    default "nptl"          if THREADS_NATIVE
+    default "linuxthreads"  if THREADS_LT
+
 if ARCH_FLOAT_SOFTFP
 comment "'softfp' ABI and uClibc is not entirely tested in crosstool-NG"
 comment "You may experience issues, although it should work just fine"