attack the biggest stack users:

-mkfs_minix_main [busybox_unstripped]:                  4288
-mkfs_minix_main [busybox_unstripped]:                  4276
-grave [busybox_unstripped]:                            4260
(bzip2 users too - not listed)

price we pay in code size increase:
mainSort                                            2458    2515     +57
grave                                               1005    1058     +53
sendMTFValues                                       2177    2195     +18
BZ2_blockSort                                        122     125      +3
mkfs_minix_main                                     3070    3022     -48
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 131/-48)            Total: 83 bytes

1 files changed, 10 insertions, 1 deletions

diff --git a/archival/bz/huffman.c b/archival/bz/huffman.c
index 02838c496..676b1af66 100644
--- a/archival/bz/huffman.c
+++ b/archival/bz/huffman.c
@@ -98,7 +98,8 @@ void DOWNHEAP1(int32_t *heap, int32_t *weight, int32_t nHeap)
 
 /*---------------------------------------------------*/
 static
-void BZ2_hbMakeCodeLengths(uint8_t *len,
+void BZ2_hbMakeCodeLengths(EState *s,
+                uint8_t *len,
                 int32_t *freq,
                 int32_t alphaSize,
                 int32_t maxLen)
@@ -110,9 +111,14 @@ void BZ2_hbMakeCodeLengths(uint8_t *len,
         int32_t nNodes, nHeap, n1, n2, i, j, k;
         Bool  tooLong;
 
+        /* bbox: moved to EState to save stack
         int32_t heap  [BZ_MAX_ALPHA_SIZE + 2];
         int32_t weight[BZ_MAX_ALPHA_SIZE * 2];
         int32_t parent[BZ_MAX_ALPHA_SIZE * 2];
+        */
+#define heap   (s->BZ2_hbMakeCodeLengths__heap)
+#define weight (s->BZ2_hbMakeCodeLengths__weight)
+#define parent (s->BZ2_hbMakeCodeLengths__parent)
 
         for (i = 0; i < alphaSize; i++)
                 weight[i+1] = (freq[i] == 0 ? 1 : freq[i]) << 8;
@@ -189,6 +195,9 @@ void BZ2_hbMakeCodeLengths(uint8_t *len,
                         weight[i] = j << 8;
                 }
         }
+#undef heap
+#undef weight
+#undef parent
 }