Create nmake file for building on Windows and fix compilation error

.gitignore

@@ -4,3 +4,7 @@ bin/
 *.a
 *.so
 *~
+
+# Object and library files on Windows
+*.lib
+*.obj

crypto_kem/kyber768/clean/Makefile.Microsoft_nmake

@@ -0,0 +1,14 @@
+LIB=libkyber768_clean.lib
+
+OBJECTS=cbd.obj indcpa.obj kem.obj kex.obj ntt.obj poly.obj polyvec.obj precomp.obj reduce.obj verify.obj
+
+CFLAGS=/I ..\..\..\common /W1 /WX # FIXME: ideally would use /W4 instead of /W1, but too many failures in Kyber right now
+
+all: $(LIB)
+
+$(LIB): $(OBJECTS)
+	LIB.EXE /OUT:$@ $**
+
+clean:
+	DEL $(OBJECTS)
+	DEL $(LIB)

crypto_kem/kyber768/clean/indcpa.c

@@ -133,7 +133,7 @@ void PQCLEAN_KYBER768_gen_matrix(polyvec *a, const unsigned char *seed,
     uint16_t val;
     unsigned int nblocks;
     const unsigned int maxnblocks = 4;
-    uint8_t buf[SHAKE128_RATE * maxnblocks];
+    uint8_t buf[SHAKE128_RATE * /* maxnblocks = */ 4];
     int i, j;
     uint64_t state[25]; // SHAKE state
     unsigned char extseed[KYBER_SYMBYTES + 2];