I have just tried to build 1.6.2 on Solaris 2.5.1.  (I have successfully
built it on 2.7, BTW.)  It failed in this way:

compiling gdbm
gcc -fPIC -g -O2 -I/home/hgs/ruby/ruby-1.6.2 -I/home/hgs/ruby/ruby-1.6.2
-I/usr/local/include -DHAVE_GDBM_H -c gdbm.c
gdbm.c:13: gdbm.h: No such file or directory
*** Error code 1
make: Fatal error: Command failed for target `gdbm.o'
Current working directory /home/hgs/ruby/ruby-1.6.2/ext/gdbm

Configure does not check for gdbm.h according to what it prints as 
it goes along.  Also: 
brains hgs 17 %> grep -i dbm config.cache
brains hgs 18 %> 
so it leave nothing in config.cache about it either.

Request for Enhancement:   that the presence of appropriate database
.h files be tested for explicitly at compile time.

Meanwhile is there a workaround?   I am building gdbm on this system.

	Hugh
	hgs / dmu.ac.uk