all: fix wildcard to work with make-4.x

In make-3.8x, the $(wildacrd) function would sort the entries,
while in make-4.x, it would just return the entries in any
unpredictable order [*]

Use the $(sort) function to get reproducible behaviour.

[*] Well, most probably the roder the entries appear when read
from readdir()

Reported-by: Andrew Ruder <andrew.ruder@elecsyscorp.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: Andrew Ruder <andrew.ruder@elecsyscorp.com>

 CT_EXPERIMENTAL=y

 CT_LOCAL_TARBALLS_DIR="${HOME}/src"

 CT_SAVE_TARBALLS=y

 CT_LOG_EXTRA=y

 CT_ARCH_LE=y

 CT_ARCH_64=y

 CT_ARCH_FLOAT_SW=y

 CT_ARCH_mips=y

 CT_TARGET_VENDOR="n32"

 CT_KERNEL_linux=y

 CT_KERNEL_V_2_6_31=y

 CT_BINUTILS_V_2_19_1a=y

 CT_CC_V_4_3_2=y

 CT_CC_LANG_CXX=y

 CT_LIBC_uClibc=y

 CT_LIBC_UCLIBC_V_0_9_30_1=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