-dnl Check for directory with kernel source... (from ALSA)
-AC_CACHE_CHECK([for directory with kernel source], tinc_cv_kerneldir,
-[ AC_ARG_WITH(kernel,
- [ --with-kernel=dir give the directory with kernel sources]
- [ (default: /usr/src/linux)],
- kerneldir="$withval", kerneldir="/usr/src/linux")
- AC_DEFINE_UNQUOTED(CONFIG_TINC_KERNELDIR, "$kerneldir")
- CONFIG_TINC_KERNELDIR="$kerneldir"
- AC_SUBST(CONFIG_TINC_KERNELDIR)
- AC_MSG_RESULT($kerneldir)
-])
-AC_CACHE_CHECK([for linux/if_tun.h], tinc_cv_linux_if_tun_h,
-[ AC_TRY_COMPILE([linux/if_tun.h],
- [int a = IFF_TAP],
- if_tun_h="linux/if_tun.h",
- [ AC_TRY_COMPILE([$kerneldir/include/linux/if_tun.h],
- [int a = IFF_TAP],
- if_tun_h="$kerneldir/include/linux/if_tun.h",
- if_tun_h="no")
+ AC_ARG_WITH(kernel,
+ AS_HELP_STRING([--with-kernel=DIR], [give the directory with kernel sources (default: /usr/src/linux)]),
+ kerneldir="$withval",
+ kerneldir="/usr/src/linux"
+ )
+
+ AC_CACHE_CHECK([for linux/if_tun.h], tinc_cv_linux_if_tun_h,
+ [
+ AC_COMPILE_IFELSE(
+ AC_LANG_PROGRAM([
+ #include "$kerneldir/include/linux/if_tun.h"
+ int a = IFF_TAP;
+ ]),
+ [if_tun_h="\"$kerneldir/include/linux/if_tun.h\""],
+ [AC_COMPILE_IFELSE(
+ AC_LANG_PROGRAM([
+ #include <linux/if_tun.h>
+ int a = IFF_TAP;
+ ]),
+ [if_tun_h="default"],
+ [if_tun_h="no"]
+ )]
+ )
+
+ if test $if_tun_h = no; then
+ tinc_cv_linux_if_tun_h=none
+ else
+ tinc_cv_linux_if_tun_h="$if_tun_h"
+ fi