libc/glibc: fix installing syscall.h when installing start-files.

Reported-by: Rafael C <groups.r2@gmail.com>
Reported-by: Jérôme BARDON <bardon.pro@gmail.com>
Reported-by: Daniel Price <daniel.price@gmail.com>
[yann.morin.1998@free.fr: use a conditional approach, also suggested by Daniel]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

CT_EXPERIMENTAL=y

CT_LOCAL_TARBALLS_DIR="${HOME}/src"

CT_SAVE_TARBALLS=y

CT_LOG_EXTRA=y

CT_ARCH_m68k=y

CT_KERNEL_linux=y

CT_KERNEL_V_3_5=y

CT_BINUTILS_V_2_21_1a=y

CT_LIBC_UCLIBC_CONFIG_FILE="${CT_LIB_DIR}/samples/${CT_TARGET}/${CT_LIBC}-${CT_LIBC_VERSION}.config"

CT_THREADS_LINUXTHREADS=y