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(-)

 # GMP options

 choice

     bool

     prompt "MPFR version"

 config MPFR_V_2_3_1

     bool

     prompt "2.3.1"

 config MPFR_V_2_3_2

     bool

     prompt "2.3.2"

 # CT_INSERT_VERSION_ABOVE

 # Don't remove above line!

 endchoice

 config MPFR_VERSION

     string

     default "2.3.1" if MPFR_V_2_3_1

     default "2.3.2" if MPFR_V_2_3_2

 # CT_INSERT_VERSION_STRING_ABOVE

 # Don't remove above line!

 config MPFR_CHECK

     bool

     prompt "Check MPFR"

     default y

     help

       It is highly recommended that 'make check' is run against the newly built

       MPFR library. See http://gmplib.org/