Work around buggy malloc() implementations that cause problems on malloc(0).

Ticket #1572. (CVS 2996)

FossilOrigin-Name: ada5490f12795a8d13d0f42077c463709c677846

manifest

@@ -1,5 +1,5 @@
-C Improve\scoverage\sof\spager.c\sand\sfix\san\sIO\serror\shandling\sbug\sfound\sin\sthe\sprocess.\s(CVS\s2995)
-D 2006-01-23T13:09:46
+C Work\saround\sbuggy\smalloc()\simplementations\sthat\scause\sproblems\son\smalloc(0).\nTicket\s#1572.\s(CVS\s2996)
+D 2006-01-23T13:14:55
 F Makefile.in ab3ffd8d469cef4477257169b82810030a6bb967
 F Makefile.linux-gcc aee18d8a05546dcf1888bd4547e442008a49a092
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -47,7 +47,7 @@ F src/func.c 96b26601c092b7b43a13e440e3f988b32a385f6a
 F src/hash.c 8747cf51d12de46512880dfcf1b68b4e24072863
 F src/hash.h 1b0c445e1c89ff2aaad9b4605ba61375af001e84
 F src/insert.c 4d37e285459af9bc2ff92ae237285b12cd5e8a71
-F src/legacy.c 0fd27db5e07a46853b9876baaa370b40e75a9b40
+F src/legacy.c 86b669707b3cefd570e34154e2f6457547d1df4f
 F src/main.c 439168db0a830efd0b9e7325aff39adc5524a1b5
 F src/md5.c c5fdfa5c2593eaee2e32a5ce6c6927c986eaf217
 F src/os.c 1d1a61cdf150e9f9520a3bc787c8465148ea2e78
@@ -344,7 +344,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
 F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513
-P 6385628edd79187dff1687815d0101c31248e54f
-R 80ef760a1dd0cc6379cc9e976317f3a0
-U danielk1977
-Z 3aafcdd526d06e6968e5956fe796cd4a
+P 6ec8e6b7856a0b394b8497ab9166b882f98124ba
+R 4458a3ccbcb564e876c75ec6f51ead97
+U drh
+Z 8a56f30daefd849decb2ee9c85f46798

manifest.uuid

@@ -1 +1 @@
-6ec8e6b7856a0b394b8497ab9166b882f98124ba
+ada5490f12795a8d13d0f42077c463709c677846

src/legacy.c

@@ -14,7 +14,7 @@
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
 **
-** $Id: legacy.c,v 1.12 2006/01/18 15:25:17 danielk1977 Exp $
+** $Id: legacy.c,v 1.13 2006/01/23 13:14:55 drh Exp $
 */
 
 #include "sqliteInt.h"
@@ -68,8 +68,8 @@ int sqlite3_exec(
     nCallback = 0;
 
     nCol = sqlite3_column_count(pStmt);
-    azCols = sqliteMalloc(2*nCol*sizeof(const char *));
-    if( nCol && !azCols ){
+    azCols = sqliteMalloc(2*nCol*sizeof(const char *) + 1);
+    if( azCols==0 ){
       goto exec_out;
     }