my first autoconf macro

[Martin Kalbfuss]

Hi,

I currently write my first atuoconf macro to detect the gm2 Modula-2
compiler for my sdl wrapper. I'm unsure about some details. And some
comments from advanced autoconf users would be nice.

Here's the code:

AC_DEFUN([ACX_PROG_GM2],
[
# Get the gm2 compiler path and check for the rquired version

m4_if([$1],[],[AC_FATAL([No gm2 major version given!])], [])

AC_MSG_CHECKING([for gm2 (>= $min_gm2_major_version)])
        
AC_CHECK_PROG([GM2], [gm2], [yes])      
if test X$GM2 = xyes ; then
        GM2="gm2"
else
        AC_MSG_RESULT([not found])
        AC_MSG_ERROR([Couldn't find GNU-Modula-2 compiler!])
fi

min_gm2_major_version=$1 
min_gm2_minor_version=m4_if([$2], ,[0],$2)
min_gm2_version=$min_gm2_major_version.$min_gm2_minor_version

error_string="Gm2 outdated. Upgrade to version >= $min_gm2_version!"
 
gm2_major_version=`$GM2 --version | \
        sed -n 's/[[^ ]]* [[^ ]]*  \([[0-9]]\).*/\1/p'`
gm2_minor_version=`$GM2 --version | \
        sed -n 's/[[^ ]]* [[^ ]]*  [[0-9]][[.]]\([[0-9]]*\).*/\1/p'`
gm2_version=$gm2_major_version.$gm2_minor_version
 
AC_MSG_RESULT([$gm2_version])
 
if test $gm2_major_version -lt $min_gm2_major_version ; then 
        AC_MSG_ERROR([$error_string])

if test $gm2_minor_version -lt $min_gm2_minor_version ; then
        AC_MSG_ERROR([$error_string])

AC_SUBST([GM2])
])