gcc: Gnu OpenMP support depends on threading

Instead of checking if thread support is enabled during the build, move
the check to kconfig-time. Since if threading support is not availble,
libgomp should not be available either.

Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>

config/cc/gcc.in.2

@@ -137,12 +137,15 @@ config CC_GCC_LIBMUDFLAP
 config CC_GCC_LIBGOMP
     bool
     prompt "Compile libgomp"
+    depends on !THREADS_NONE
     help
       libgomp is "the GNU implementation of the OpenMP Application Programming
       Interface (API) for multi-platform shared-memory parallel programming in
       C/C++ and Fortran". See:
         http://gcc.gnu.org/onlinedocs/libgomp/
 
+      GNU OpenMP support requires threading.
+
       The default is 'N'. Say 'Y' if you need it, and report success/failure.
 
 config CC_GCC_LIBSSP

scripts/build/cc/100-gcc.sh

@@ -816,7 +816,6 @@ do_gcc_backend() {
 
     if [ "${CT_THREADS}" = "none" ]; then
         extra_config+=("--disable-threads")
-	extra_config+=("--disable-libgomp")
     else
         if [ "${CT_THREADS}" = "win32" ]; then
             extra_config+=("--enable-threads=win32")