AIX support

[solardiz]

With the changes in #32, this almost builds on AIX. We should be able to fix it to fully build and work if there's demand.

solar@gcc111:[/home/solar/passwdqc]make
        case "`uname -s`" in  Linux)    make CPPFLAGS_lib=" -DPACKAGE=\\\"passwdqc\\\" -DHAVE_SHADOW"  LDFLAGS_lib=" --shared  -Wl,--soname,libpasswdqc.so.1,--version-script,libpasswdqc.map"  LDFLAGS_pam=" --shared  -Wl,--version-script,pam_passwdqc.map"  LDLIBS_pam="-lpam -lcrypt"  all_wrapped;;  SunOS)       make -e CPPFLAGS_lib=" -DPACKAGE=\\\"passwdqc\\\" -DHAVE_SHADOW"  LD_lib=/usr/ccs/bin/ld  LDFLAGS_lib=" -G"  LDFLAGS_pam=" -G"  LDLIBS_pam="-lpam -lcrypt"  INSTALL="/usr/ucb/install -c"  SHARED_LIBDIR="/usr/lib"  SECUREDIR="/usr/lib/security"  all_wrapped;;  HP-UX)       make CPPFLAGS_lib=" -DPACKAGE=\\\"passwdqc\\\" -DHAVE_SHADOW"  LD_lib=ld  LDFLAGS_lib=" -b"  LDFLAGS_pam=" -b"  LDLIBS_pam="-lpam -lsec"  all_wrapped;;  Darwin)        make  SHARED_LIB="libpasswdqc.0.dylib"  DEVEL_LIB="libpasswdqc.dylib"  SECUREDIR="/usr/lib/pam"  LDLIBS_pam="-lpam -lSystem"  all_wrapped;;  CYGWIN_NT*) make CPPFLAGS_lib=" -DPACKAGE=\\\"passwdqc\\\""  SHARED_LIB="cygpasswdqc-0.dll"  SHARED_LIBDIR="/usr/bin"  DEVEL_LIB="libpasswdqc.dll.a"  LDFLAGS_lib=" --shared  -Wl,--out-implib=libpasswdqc.dll.a  -Wl,--export-all-symbols  -Wl,--enable-auto-import"  BINS="pwqgen pwqcheck pwqfilter cygpasswdqc-0.dll"  CYGWIN=true  all_wrapped;;  *)  make all_wrapped;;  esac
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c pam_passwdqc.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c passwdqc_memzero.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c concat.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c md4.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c passwdqc_check.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c passwdqc_filter.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c passwdqc_load.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c passwdqc_parse.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c passwdqc_random.c
<command-line>: warning: missing terminating " character
        gcc  -DPACKAGE=\\\"passwdqc\\\" -Wall -W -O2 -fPIC -c wordset_4k.c
<command-line>: warning: missing terminating " character
        gcc  --shared concat.o md4.o passwdqc_check.o passwdqc_filter.o passwdqc_load.o passwdqc_memzero.o passwdqc_parse.o passwdqc_random.o wordset_4k.o  -o libpasswdqc.so.1
        if [ "" != true ]; then  ln -s -f libpasswdqc.so.1 libpasswdqc.so;  fi
        gcc  --shared pam_passwdqc.o passwdqc_memzero.o -lpam -lcrypt -L. -lpasswdqc -o pam_passwdqc.so
ld: 0706-006 Cannot find or open library file: -l passwdqc
        ld:open(): A file or directory in the path name does not exist.
collect2: error: ld returned 255 exit status
make: 1254-004 The error code from the last command is 1.