UPDATE: Problem solved following the advice of bitingduck. After installing the new Xcode, run Xcode and open the Preferences dialog. Click the Downloads icon and the Components tab, and then install the command line tools. Then the CPAN installs work.
I upgraded to Mountain Lion (OS X 10.8) and my Perl DBI scripts are no longer working. The last time this happened (when upgrading to Lion, OS X 10.7), I installed the latest version of Xcode and then was able to re-install DBI and DBD::mysql with the CPAN module.
This time I have installed the latest version of Xcode (4.5.1), and "install DBI" or "install DBD::mysql" both fail with this error message:
+1: fatal error:
'sys/types.h' file not found
# include <sys/types.h>
1 error generated.
make: *** [Perl.o] Error 1
Can anybody help?