cd C:/bitcoin/src/leveldb && CC=gcc CXX=g++ TARGET_OS=OS_WINDOWS_CROSSCOMPILE mi
ngw32-make OPT="-pipe -fno-keep-inline-dllexport -D_FORTIFY_SOURCE=2 -O2" liblev
eldb.a libmemenv.a && ranlib C:/bitcoin/src/leveldb/libleveldb.a && ranlib C:/bi
tcoin/src/leveldb/libmemenv.a
'CC' is not recognized as an internal or external command,
operable program or batch file.
Makefile.Release:301: recipe for target 'c:/bitcoin/src/leveldb/libleveldb.a' failed
mingw32-make: *** [c:/bitcoin/src/leveldb/libleveldb.a] Error 1
I think you're skipping some important (analysis) steps in solving it. As I read this output, it's telling you that "CC" is not a recognized command. As far as I know, the command line as entered will generate this error as long as CC isn't a recognized command because "cd [blah blah blah] && [X]" means to change the active directory and then (assuming the directory existed and was accessible and therefore the cd command succeeded) execute X, and in Windows, "CC" really isn't a recognized command.
The command line comes from the mingw32-make executable, which appears to run under the assumption that it is in a shell that allows command-line variable assignments without using "SET" (as in "SET CC=gcc"), and the shell you're running doesn't allow that. If mingw32-make created a command line that used SET (as in "cd [blah blah blah] && SET CC=gcc...", then maybe it would get past that part, but if I'm right about what mingw32-make needs in the shell it invokes, you'll get other errors anyway.
My best guess is that mingw32-make will invoke a shell that is supposed to be a minGW shell, and something about your setup causes it to invoke a non-MinGW shell.
I am extremely rusty, so there's a lot of guesswork in what I wrote. If anyone reads that and sees an error in my guesswork, I'd very much appreciate if you point it out to me.
The main point I wanted to stress is that every error provides specific details that we ought not just ignore. In this case, the fact is that it interpreted your use of CC as "an internal or external command, operable program or batch file," and you definitely are not using it that way. When you track down the exact problem, you learn a lot along the way and expand your ability to help others.