Drop custom compilation and link flags
    
    They were added in this form in the initial commit.
    I think it's hard to say at this point what if anything needs to be customized
    like that. Let's try to go back to the defaults and see what happens.
    
    (before)
    libtool: link: gcc -m64 -O2 -fPIC -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -O2 -g -Wl,-z -Wl,noexecstack -o hydra_nameserver tools/nameserver/hydra_nameserver-hydra_nameserver.o  /builddir/build/BUILD/mpich-3.2.1/src/pm/hydra/.libs/libhydra.a mpl/.libs/libmpl.a -lpthread -lhwloc
    (after)
    libtool: link: gcc -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -O2 -g -Wl,-z -Wl,relro -Wl,--as-needed -Wl,-z -Wl,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -o hydra_nameserver tools/nameserver/hydra_nameserver-hydra_nameserver.o  /builddir/build/BUILD/mpich-3.2.1/src/pm/hydra/.libs/libhydra.a mpl/.libs/libmpl.a -lpthread -lhwloc