Fix the sqldiff utility program so that it works for schemas that have

tables with zero-length column names.

FossilOrigin-Name: 64263ccb8f9835c615242de6e28db24f953422fa

manifest

@@ -1,5 +1,5 @@
-C Improvements\sto\stemporary\sfile\screation\slogic\sin\sthe\sunix\sVFS.
-D 2015-11-28T21:49:53.832
+C Fix\sthe\ssqldiff\sutility\sprogram\sso\sthat\sit\sworks\sfor\sschemas\sthat\shave\ntables\swith\szero-length\scolumn\snames.
+D 2015-11-29T21:46:19.675
 F Makefile.in d828db6afa6c1fa060d01e33e4674408df1942a1
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc e928e68168df69b353300ac87c10105206653a03
@@ -1394,7 +1394,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 7ce07da76b5e745783e703a834417d725b7d45fd
 F tool/split-sqlite3c.tcl d9be87f1c340285a3e081eb19b4a247981ed290c
-F tool/sqldiff.c db1232df457fdd4cbf2a919a497fc44bb18fb933
+F tool/sqldiff.c 653db1a9294e0b34849c4504599c282a18d8b8c6
 F tool/stack_usage.tcl f8e71b92cdb099a147dad572375595eae55eca43
 F tool/symbols-mingw.sh 4dbcea7e74768305384c9fd2ed2b41bbf9f0414d
 F tool/symbols.sh fec58532668296d7c7dc48be9c87f75ccdb5814f
@@ -1405,7 +1405,7 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 7c6a809e25138950f50554e1fb96e0b6ebbe0bd4
-R ca93330e61d31cc358456a5d19f9fb0f
+P d6e177fd09c83d46adc5b5d36e9a439aa5397450
+R 6d96f803f67943fdc4d03a972304e707
 U drh
-Z a3585e71cbbc630dcd21f2a2025e8592
+Z e1ff9fd256204ded8600114936035e27

manifest.uuid

@@ -1 +1 @@
-d6e177fd09c83d46adc5b5d36e9a439aa5397450
+64263ccb8f9835c615242de6e28db24f953422fa

tool/sqldiff.c

@@ -155,6 +155,7 @@ static char *safeId(const char *zId){
     "WITH", "WITHOUT",
   };
   int lwr, upr, mid, c, i, x;
+  if( zId[0]==0 ) return sqlite3_mprintf("\"\"");
   for(i=x=0; (c = zId[i])!=0; i++){
     if( !isalpha(c) && c!='_' ){
       if( i>0 && isdigit(c) ){