fix #187: remove errors exposed by undefined behavior sanitizer

Move decrement in loop to avoid the following errors:
adler32.c:91:19: runtime error: unsigned integer overflow: 0 - 1 cannot be represented in type 'size_t' (aka 'unsigned long')
adler32.c:136:19: runtime error: unsigned integer overflow: 0 - 1 cannot be represented in type 'size_t' (aka 'unsigned long')
inflate.c:972:32: runtime error: unsigned integer overflow: 0 - 1 cannot be represented in type 'unsigned int'

Fix the following bugs as recommended by Mika Lindqvist:
arch/x86/deflate_quick.c:233:22: runtime error: unsigned integer overflow: 0 - 1 cannot be represented in type 'unsigned int'
arch/x86/fill_window_sse.c:52:28: runtime error: unsigned integer overflow: 1 - 8192 cannot be represented in type 'unsigned int'

1 files changed, 3 insertions, 1 deletions

diff --git a/inflate.c b/inflate.c
index bbab72e..469dde6 100644
--- a/inflate.c
+++ b/inflate.c
@@ -969,8 +969,10 @@ int ZEXPORT PREFIX(inflate)(PREFIX3(stream) *strm, int flush) {
                         state->mode = BAD;
                         break;
                     }
-                    while (copy--)
+                    while (copy) {
+                        --copy;
                         state->lens[state->have++] = (uint16_t)len;
+                    }
                 }
             }