fix some bugs that cppcheck found

cdb/cdb.c

@@ -49,7 +49,7 @@ void cdb_init(struct cdb *c,int64 fd) {
   if (fstat(fd,&st) == 0)
     if (st.st_size <= 0xffffffff) {
       x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0);
-      if (x + 1) {
+      if (x != MAP_FAILED) {
 	c->size = st.st_size;
 	c->map = x;
       }

test/range.c

@@ -108,7 +108,7 @@ void check_rangeptrbuf() {
   {
     uint16_t y[6];
     int i;
-    for (i=0; i<7; ++i) y[i]="fnord"[i];
+    for (i=0; i<6; ++i) y[i]="fnord"[i];
     assert(range_str2inbuf(y,5*2,y)==0);
     assert(range_str2inbuf(y,5*2+1,y)==0);
     assert(range_str2inbuf(y,sizeof(y),y)==1);
@@ -122,7 +122,7 @@ void check_rangeptrbuf() {
   {
     uint32_t y[6];
     int i;
-    for (i=0; i<7; ++i) y[i]="fnord"[i];
+    for (i=0; i<6; ++i) y[i]="fnord"[i];
     assert(range_str4inbuf(y,5*4,y)==0);
     assert(range_str4inbuf(y,5*4+3,y)==0);
     assert(range_str4inbuf(y,sizeof(y),y)==1);

windoze.h

@@ -8,13 +8,13 @@ extern "C" {
 int winsock2errno(long l);
 void __winsock_init(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #else
 
 #define winsock2errno(fnord) (fnord)
 #define __winsock_init()
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif