Missing -ldl in master?

[Phil Mayers]

I'm getting:

/usr/bin/ld: modules.o: undefined reference to symbol 'dlopen@@GLIBC_2.1'
/usr/bin/ld: note: 'dlopen@@GLIBC_2.1' is defined in DSO /lib/libdl.so.2 
so try adding it to the linker command line
/lib/libdl.so.2: could not read symbols: Invalid operation
collect2: ld returned 1 exit status

...when building recent master on Fedora 14 (but not RHEL5, oddly). 
Adding "-ldl" to LIBS in Make.inc fixes this, but I guess it should be a 
configure check?