configure: On Mac OS X, always specify target architecture to the dev tools.

Fixes building on Snow Leopard.  Mac OS X doesn't have a concept of one
bit-ness being "native".  So, which architecture gets built is somewhat
arbitrary.  On Snow Leopard, the tools have changed to default to building
64-bit, which causes us problems.  So, just always be explicit.

configure

@@ -3811,6 +3811,29 @@ fi
 
 
 case $host in
+  *-darwin*)
+    if test "x$enable_win64" == "xyes"
+    then
+      CC="$CC -m64"
+      CXX="$CXX -m64"
+      LD="${LD:-ld} -arch x86_64"
+      AS="${AS:-as} -arch x86_64"
+      host_cpu="x86_64"
+      notice_platform="64-bit "
+      TARGETFLAGS="-m64"
+
+    else
+      CC="$CC -m32"
+      CXX="$CXX -m32"
+      LD="${LD:-ld} -arch i386"
+      AS="${AS:-as} -arch i386"
+      host_cpu="i386"
+      notice_platform="32-bit "
+      TARGETFLAGS="-m32"
+
+      enable_win16=${enable_win16:-yes}
+    fi
+    ;;
   x86_64*)
     if test "x$enable_win64" != "xyes" -a "$cross_compiling" != "yes"
     then

configure.ac

@@ -102,6 +102,27 @@ dnl We can't use AC_PROG_CPP for winegcc, it uses by default $(CC) -E
 AC_CHECK_TOOL(CPPBIN,cpp,cpp)
 
 case $host in
+  *-darwin*)
+    if test "x$enable_win64" == "xyes"
+    then
+      CC="$CC -m64"
+      CXX="$CXX -m64"
+      LD="${LD:-ld} -arch x86_64"
+      AS="${AS:-as} -arch x86_64"
+      host_cpu="x86_64"
+      notice_platform="64-bit "
+      AC_SUBST(TARGETFLAGS,"-m64")
+    else
+      CC="$CC -m32"
+      CXX="$CXX -m32"
+      LD="${LD:-ld} -arch i386"
+      AS="${AS:-as} -arch i386"
+      host_cpu="i386"
+      notice_platform="32-bit "
+      AC_SUBST(TARGETFLAGS,"-m32")
+      enable_win16=${enable_win16:-yes}
+    fi
+    ;;
   x86_64*)
     if test "x$enable_win64" != "xyes" -a "$cross_compiling" != "yes"
     then