Further enhance the check for needed tools:
- update the tool_pattern to use ' || ' as a pattern separator
- which allows using | in regexp
- add checks for cut and xargs
- manually check for grep and sed because they are needed when checking for tools
- print why a test failed, with each tested tool and regexp
- move tools checks before options parsing
- apply conttibutions before computing the version string
- inform user to run make && make install

/trunk/configure | 173 111 62 0 ++++++++++++++++++++++++++++++++++++++++----------------------
1 file changed, 111 insertions(+), 62 deletions(-)

 diff -dur strace-4.5.15.orig/system.c strace-4.5.15/system.c

 --- strace-4.5.15.orig/system.c	2007-01-17 00:22:36.000000000 +0100

 +++ strace-4.5.15/system.c	2007-07-14 19:28:41.000000000 +0200

 @@ -1612,7 +1612,9 @@

  	{ CTL_KERN, "CTL_KERN" },

  	{ CTL_VM, "CTL_VM" },

  	{ CTL_NET, "CTL_NET" },

 +#ifdef CTL_PROC

  	{ CTL_PROC, "CTL_PROC" },

 +#endif

  	{ CTL_FS, "CTL_FS" },

  	{ CTL_DEBUG, "CTL_DEBUG" },

  	{ CTL_DEV, "CTL_DEV" },