complibs/cloog: create missing m4 dir

Because we now patch configure.in and configure, the Makefile quicks
in a re-build rule as the source files are now more recent than the
bundled generated files, and that fails because the m4 directory
is missing, although on some systems where aclocal is not installed,
the re-build rule does nothing (except a warning).

Always create tht directory.

Reported-by: Per Arnold Blaasmo <per-arnold.blaasmo@atmel.com>
[Also thanks to Thomas De Schampheleire <patrickdepinguin@gmail.com>
for some digging works on this issue]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# mingw options

## depends on MINGW32

##

## select LIBC_SUPPORT_WIN32THREADS

##

## help The de-facto standard for Mingw distributions.

choice

    bool

    prompt "Mingw runtime version"

# Don't remove next line

# CT_INSERT_VERSION_BELOW

config MINGWRT_V_3_18

    bool

    prompt "3.18"

config MINGWRT_V_select

    bool

    prompt "Other version"

endchoice

config MINGWRT_VERSION

    string

    prompt "Mingw runtime version" if MINGWRT_V_select

# Don't remove next line

# CT_INSERT_VERSION_STRING_BELOW

    default "3.18" if MINGWRT_V_3_18

    help

      Enter the version number of the mingw runtime files to use