crosstool-ng: fix libstdc++ configuration for canadian builds

libstdc++-v3/configure script can't find crt0.o to compile executable.
After this it attempts to verify if libc features are enabled using only
preprocessing, leading to false-positive results.

This problem appeared only for canadian builds.

crosstool-ng#2110

scripts/crosstool-NG.sh

@@ -361,10 +361,8 @@ if [ -z "${CT_RESTART}" ]; then
         # binutils 2.14 and later obey it, older binutils ignore it.
         # Lets you build a working 32->64 bit cross gcc
         CT_BINUTILS_SYSROOT_ARG="--with-sysroot=${CT_SYSROOT_DIR}"
-        # Use --with-headers, else final gcc will define disable_glibc while
-        # building libgcc, and you'll have no profiling
-        CT_CC_CORE_SYSROOT_ARG=("--without-headers")
-        CT_CC_SYSROOT_ARG=("--with-headers=${CT_HEADERS_DIR}")
+        CT_CC_CORE_SYSROOT_ARG=("--with-sysroot=${CT_SYSROOT_DIR}" "--with-native-system-header-dir=/include")
+        CT_CC_SYSROOT_ARG=("--with-sysroot=${CT_SYSROOT_DIR}" "--with-native-system-header-dir=/include")
     fi
     CT_DoExecLog ALL mkdir -p "${CT_SYSROOT_DIR}"
     CT_DoExecLog ALL mkdir -p "${CT_DEBUGROOT_DIR}"