configure: disable static linking on Darwin

Static liunking is not supported on Darwin, so hide the corresponding
options when the build machine is Darwin.

Reported-by: Andrea Franceschini <therealmorpheu5@gmail.com>
Reported-by: Bryan Hundven <bryanhundven@gmail.com>
Reported-by: "Titus von Boxberg" <titus@v9g.de>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

config/cc/gcc.in.2

@@ -44,6 +44,7 @@ config CC_STATIC_LIBSTDCXX
     bool
     prompt "Link libstdc++ statically into the gcc binary"
     default y
+    depends on CONFIGURE_static_link_ok
     depends on CONFIGURE_has_static_libstdcxx
     depends on CC_GCC_4_4_or_later
     help

config/debug/gdb.in.cross

@@ -24,6 +24,7 @@ if GDB_CROSS
 config GDB_CROSS_STATIC
     bool
     prompt "Build a static cross gdb"
+    depends on CONFIGURE_static_link_ok
     depends on CONFIGURE_has_static_expat
     help
       A static cross gdb can be usefull if you debug on a machine that is

config/toolchain.in

@@ -51,6 +51,7 @@ config SYSROOT_DIR_PREFIX
 config STATIC_TOOLCHAIN_POSSIBLE
     bool
     default y
+    depends on CONFIGURE_static_link_ok
     depends on CONFIGURE_has_static_libstdcxx
     # Add new deps here! :-)
 

configure

@@ -449,6 +449,30 @@ case "${host}" in
         ;;
 esac
 
+printf "Checking if static linking is possible... "
+static_link_ok=""
+case "${host}" in
+    Darwin) ;;
+    *)  tmp=.static.tmp
+        if gcc -xc - -static -o "${tmp}" >/dev/null 2>&1<<-_EOF_
+				int main() { return 0; }
+			_EOF_
+        then
+            static_link_ok="y"
+        fi
+        rm -f "${tmp}"
+        ;;
+esac
+if [ "${static_link_ok}" = "y" ]; then
+    printf "yes\n"
+else
+    printf "no\n"
+    printf " * An optional host feature is missing, some features will be disabled:\n"
+    printf " * - It will not be possible to statically link toolchain's binaries\n"
+fi
+add_to_kconfig_list static_link_ok
+
+# Library checks
 ncurses_hdrs="ncurses/ncurses.h ncurses/curses.h ncurses.h curses.h"
 ncurses_libs="$( for l in ncursesw ncurses curses; do   \
                      for x in so a dylib; do            \