Problem with ./configure in gtkmm

["PMB81 telefonica net" <PMB81 telefonica net>]

Hello, my name is Pablo, i'm from Malaga(Spain) and i want that you can
help me with this problem.

I'm programing with C++ and i must to use GTK+.

My problem begin when i execute ./configure of gtkmm-1.2.8 package and
system print:

loading cache ./config.cache
checking for a BSD compatible install... (cached) /usr/bin/install -c
checking whether build environment is sane... yes
checking whether make sets ${MAKE}... (cached) yes
checking for working aclocal... found
checking for working autoconf... found
checking for working automake... found
checking for working autoheader... found
checking for working makeinfo... found
checking whether to enable maintainer-specific portions of Makefiles... no
checking for gcc... (cached) gcc
checking whether the C compiler (gcc  ) works... yes
checking whether the C compiler (gcc  ) is a cross-compiler... no
checking whether we are using GNU C... (cached) yes
checking whether gcc accepts -g... (cached) yes
checking how to run the C preprocessor... (cached) gcc -E
checking for flex... (cached) flex
checking for flex... (cached) flex
checking for yywrap in -lfl... (cached) yes
checking lex output file root... (cached) lex.yy
checking whether yytext is a pointer... (cached) yes
checking for bison... (cached) bison -y
checking whether make sets ${MAKE}... (cached) yes
checking host system type... i686-pc-linux-gnu
checking build system type... i686-pc-linux-gnu
checking for ranlib... (cached) ranlib
checking for ld used by GCC... (cached) /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... (cached) yes
checking for BSD-compatible nm... (cached) /usr/bin/nm -B
checking whether ln -s works... (cached) yes
checking for object suffix... o
checking for executable suffix... no
checking for gcc option to produce PIC... -fPIC
checking if gcc PIC flag -fPIC works... yes
checking if gcc supports -c -o file.o... yes
checking if gcc supports -c -o file.lo... yes
checking if gcc supports -fno-rtti -fno-exceptions ... no
checking if gcc static flag -static works... -static
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking whether the linker (/usr/bin/ld) supports shared libraries... yes
checking command to parse /usr/bin/nm -B output... ok
checking how to hardcode library paths into programs... immediate
checking for /usr/bin/ld option to reload object files... -r
checking dynamic linker characteristics... Linux ld.so
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... no
checking for objdir... .libs
creating libtool
loading cache ./config.cache
checking for gm4... no
checking for m4... m4
checking for sgml2html... sgml2html
checking whether m4 is GNU m4... yes
checking for perl5... no
checking for perl... perl
checking whether make is GNU Make... yes
checking for gtk-config... /usr/bin/gtk-config
checking for GTK - version >= 1.2.7... yes
checking if html documentation and manual pages are generated... no
checking for c++... c++
checking whether the C++ compiler (c++  ) works... yes
checking whether the C++ compiler (c++  ) is a cross-compiler... no
checking whether we are using GNU C++... yes
checking whether c++ accepts -g... yes
checking what warning flags to pass to the C++ compiler... -Wall -Wno-unused
checking what language compliance flags to pass to the C++ compiler... 
checking for sigc-config... no
checking for libsigc++ - version >= 0.8.5... configure: error: Libsigc++
is required to compile Gtk--. If libsigc++ was installed
but no found to be sane,  most likely you have not placed the 
/usr/local/lib path in the library config file and run ldconfig.

I have installed libsigc++ and i modify PATH, PKG_CONFIG_PATH but i
don't uunderstand wich is the problem. So, what can i do?

Thank you.