Thank you very much for responding Ken
I have to admit that if I am a newbie now then when I took "control" of my computer I was an ultimate newbie. Of course I always tried to act with safety but you never know, so it's possible that I have mixed up some settings of the poor machine and maybe that's why I have problems now
Anyway I tryied to follow your instructions (configure-help and LDFLAGS=-lm) and this way produced another long post

My sincere apologies
1) This is what I got from
./configure --help| less
`configure' configures this package to adapt to many kinds of systems.
Usage: ./configure [OPTION]... [VAR=VALUE]...
To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE. See below for descriptions of some of the useful variables.
Defaults for the options are specified in brackets.
Configuration:
-h, --help display this help and exit
--help=short display options specific to this package
--help=recursive display the short help of all the included packages
-V, --version display version information and exit
-q, --quiet, --silent do not print `checking...' messages
--cache-file=FILE cache test results in FILE [disabled]
-C, --config-cache alias for `--cache-file=config.cache'
-n, --no-create do not create output files
--srcdir=DIR find the sources in DIR [configure dir or `..']
Installation directories:
--prefix=PREFIX install architecture-independent files in PREFIX
[/usr/local]
--exec-prefix=EPREFIX install architecture-dependent files in EPREFIX
[PREFIX]
By default, `make install' will install all the files in
`/usr/local/bin', `/usr/local/lib' etc. You can specify
an installation prefix other than `/usr/local' using `--prefix',
for instance `--prefix=$HOME'.
For better control, use the options below.
Fine tuning of the installation directories:
--bindir=DIR user executables [EPREFIX/bin]
--sbindir=DIR system admin executables [EPREFIX/sbin]
--libexecdir=DIR program executables [EPREFIX/libexec]
--datadir=DIR read-only architecture-independent data [PREFIX/share]
--sysconfdir=DIR read-only single-machine data [PREFIX/etc]
--sharedstatedir=DIR modifiable architecture-independent data [PREFIX/com]
--localstatedir=DIR modifiable single-machine data [PREFIX/var]
--libdir=DIR object code libraries [EPREFIX/lib]
--includedir=DIR C header files [PREFIX/include]
--oldincludedir=DIR C header files for non-gcc [/usr/include]
--infodir=DIR info documentation [PREFIX/info]
--mandir=DIR man documentation [PREFIX/man]
Some influential environment variables:
CC C compiler command
CFLAGS C compiler flags
LDFLAGS linker flags, e.g. -L<lib dir> if you have libraries in a nonstandard directory <lib dir>
CPPFLAGS C/C++ preprocessor flags, e.g. -I<include dir> if you have headers in a nonstandard directory <include dir>
CPP C preprocessor
Use these variables to override the choices made by `configure' or to help
it to find libraries and programs with nonstandard names/locations.
LDFLAGS is mentioned but (call me a newbie) it gives me no hint at all
2) I also tried typing
LDFLAGS=-lm
in the command line before configure and make
This caused no change at all to the output of ./configure but it did change the output of make:
kostas@linux:~/utils/udunits/udunits-1.12.4/src> make
making `all' in directory /home/kostas/utils/udunits/udunits-1.12.4/src/port
make[1]: Entering directory `/home/kostas/utils/udunits/udunits-1.12.4/src/port'
making `all' in directory /home/kostas/utils/udunits/udunits-1.12.4/src/port/misc
make[2]: Entering directory `/home/kostas/utils/udunits/udunits-1.12.4/src/port/misc'
cc -c -g -O2 -I. -D_REENTRANT uddummy.c
ar rcuv libudport.a uddummy.o
a - uddummy.o
case "" in \
'') ;; \
*) ar rucv libudport.a ;; \
esac
ranlib libudport.a
make[2]: Leaving directory `/home/kostas/utils/udunits/udunits-1.12.4/src/port/misc'
returning to directory /home/kostas/utils/udunits/udunits-1.12.4/src/port
making `all' in directory /home/kostas/utils/udunits/udunits-1.12.4/src/port/cfortran
make[2]: Entering directory `/home/kostas/utils/udunits/udunits-1.12.4/src/port/cfortran'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/home/kostas/utils/udunits/udunits-1.12.4/src/port/cfortran'
returning to directory /home/kostas/utils/udunits/udunits-1.12.4/src/port
make[1]: Leaving directory `/home/kostas/utils/udunits/udunits-1.12.4/src/port'
returning to directory /home/kostas/utils/udunits/udunits-1.12.4/src
making `all' in directory /home/kostas/utils/udunits/udunits-1.12.4/src/lib
make[1]: Entering directory `/home/kostas/utils/udunits/udunits-1.12.4/src/lib'
ln -s ../port/misc/udalloc.c .
ln -s ../port/misc/udalloc.h .
cc -c -g -O2 -I../port/misc -I../port/cfortran -DUT_DEFAULT_PATH='"/home/kostas/utils/udunits/udunits-1.12.4/etc/udunits.dat"' utlib.c
In file included from utlib.c:29:
../port/cfortran/cfortran.h:132:3: error: #error "cfortran.h: Can't find your environment among: - MIPS cc and f77 2.0. (e.g. Silicon Graphics, DECstations, ...) - IBM AIX XL C and FORTRAN Compiler/6000 Version 01.01.0000.0000 - VAX VMS CC 3.1 and FORTRAN 5.4. - Alpha VMS DEC C 1.3 and DEC FORTRAN 6.0. - Alpha OSF DEC C and DEC Fortran for OSF/1 AXP Version 1.2 - Apollo DomainOS 10.2 (sys5.3) with f77 10.7 and cc 6.7. - CRAY - NEC SX-4 SUPER-UX - CONVEX - Sun - PowerStation Fortran with Visual C++ - HP9000s300/s700/s800 Latest test with: HP-UX A.08.07 A 9000/730 - LynxOS: cc or gcc with f2c. - VAXUltrix: vcc,cc or gcc with f2c. gcc or cc with f77. - f77 with vcc works; but missing link magic for f77 I/O. - NO fort. None of gcc, cc or vcc generate required names. - f2c : Use #define f2cFortran, or cc -Df2cFortran - NAG f90: Use #define NAGf90Fortran, or cc -DNAGf90Fortran - Absoft UNIX F77: Use #define AbsoftUNIXFortran or cc -DAbsoftUNIXFortran - Absoft Pro Fortran: Use #define AbsoftProFortran - Portland Group Fortran: Use #define pgiFortran"
make[1]: *** [utlib.o] Error 1
make[1]: Leaving directory `/home/kostas/utils/udunits/udunits-1.12.4/src/lib'
make: *** [lib/all] Error 1
Any other ideas anybody?