Hi,

in m4/libtool.m4, the handling of spaces after -{L,R,l} for parsing
linker commands looks as follows:

  case $prev$p in
    -L* | -R* | -l*)
      # Some compilers place space between "-{L,R}" and the path.
      # Remove the space.
      if test x-L = "$p" ||
         test x-R = "$p"; then
         prev=$p
         continue
      fi

This seems to be broken for two reasons:
1. The case handling captures -l, but the following tests consider only
-L and -R.
2. The tests for equality use an x on the left side, but not on the
right side.

A working code should look as follows (patch is attached):

  case $prev$p in
    -L* | -R* | -l*)
      # Some compilers place space between "-{L,R,l}" and the path.
      # Remove the space.
      if test x-L = "x$p" ||
         test x-R = "x$p" ||
         test x-l = "x$p"; then
         prev=$p
         continue
      fi

I stumbled across this bug when using gfortran (5.3.1) which emits the
following (valid) line:

  Driving: gfortran -v conftest.o -l gfortran -l m -shared-libgcc

The current (broken) libtool leads to "-l -l" in the "postdeps_FC"
variable. After the fix, the correct "-lgfortran -lm" appears.


Best regards,
Michael