AC_FC_LIBRARY_LDFLAGS

[Christopher Hulbert]

I couldn't find any other solution to this, but when getting the library
flags of pgf90 with -Mconcur (Runs pgipa) there is an empty -l in an ignore
string pasted below.  This messes up the FCLIBS later and makes the compiler
complain becuase it lumps the next argument as the library name.

/usr/local/pgi/linux86-64/6.0/bin/pgipa -v -finalo conftest -ignore
'-Mextract -L -I -Mkeepasm -Mpreprocess -l -Minline' -nop   .....

I was able to solve this by adding
-l)
    ;;

to the configure script.  I tried adding it to fortran.m4, but rerunning
autoconf on configure.ac doesn't put the code in the configure script.