configure.ac: respect 'g' variants of libtool/libtoolize

BSD OS'es (OS X for me) provide GNU tools with prefixed 'g'. To find correct
versions of libtool/libtoolize on those systems search also for
glibtool/glibtoolize.

Signed-off-by: Andreas Bießmann <andreas@biessmann.de>
Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>
[yann.morin.1998@free.fr: search for the g-variant first]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <2f1530b54afcb6a00e1d.1395158786@andreas-mbp.er.biessmann.org>
Patchwork-Id: 331467

CT_LOCAL_TARBALLS_DIR="${HOME}/src"

CT_SAVE_TARBALLS=y

CT_LOG_EXTRA=y

CT_ARCH_blackfin=y

CT_KERNEL_linux=y

CT_KERNEL_V_2_6_33=y

CT_ARCH_BINFMT_FDPIC=y

CT_BINUTILS_V_2_20_1a=y

CT_CC_V_4_3_4=y

CT_LIBC_UCLIBC_V_0_9_30_2=y

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

CT_GMP_V_4_3_2=y

CT_MPFR_V_2_4_2=y