Drop linker flags from mingn linker script.
Drop linker flags from mingn linker script.

Linker scripts group sections can only contain libraries.
Listing cli_main and nacl_spawn explicitly rather than
a variable that expands to include linker flags.

Without this bare executables no longer link correctly in the devenv
when passed -lmingn.

BUG=None
TEST=manual in devenv
R=sbc@chromium.org

Review URL: https://codereview.chromium.org/1058253005

yeyus/naclports,yeyus/naclports,yeyus/naclports,yeyus/naclports,yeyus/naclports,yeyus/naclports