Try fixing Travis and Appveyor

The new re-entrant parser requires Bison 3, which is not installed
on macOS by default. It also appears to require -Wno-yacc.

.travis.yml

@@ -85,6 +85,7 @@ jobs:
         - bison
     env:
       - CONFIGURE_FLAGS="--with-iodbc=/usr/local/opt --disable-glib"
+      - YACC="/usr/local/opt/bison/bin/bison"
   - compiler: clang
     os: osx
     osx_image: xcode11.4
@@ -96,6 +97,7 @@ jobs:
         - bison
     env:
       - CONFIGURE_FLAGS="--with-iodbc=/usr/local/opt --enable-glib"
+      - YACC="/usr/local/opt/bison/bin/bison"
   - compiler: clang
     os: osx
     osx_image: xcode11.4
@@ -106,6 +108,7 @@ jobs:
         - bison
     env:
       - CONFIGURE_FLAGS="--with-unixodbc=/usr/local/opt --disable-glib"
+      - YACC="/usr/local/opt/bison/bin/bison"
   - compiler: clang
     os: osx
     osx_image: xcode11.4
@@ -117,6 +120,7 @@ jobs:
         - bison
     env:
       - CONFIGURE_FLAGS="--with-unixodbc=/usr/local/opt --enable-glib"
+      - YACC="/usr/local/opt/bison/bin/bison"
   - compiler: gcc
     os: osx
     osx_image: xcode11.4

README.md

@@ -93,7 +93,7 @@ First, you must have reasonably current installations of:
 * [autoconf](https://www.gnu.org/software/autoconf/) (version >= 2.58)
 
 If you want to build the SQL engine, you'll need
-[bison](https://www.gnu.org/software/bison/) or
+[bison](https://www.gnu.org/software/bison/) (version >= 3.0) or
 [byacc](https://invisible-island.net/byacc/byacc.html), and
 [flex](https://github.com/westes/flex).
 

configure.ac

@@ -53,6 +53,7 @@ if $YACC -V >/dev/null 2>&1; then
     if $YACC -Wno-conflicts-sr -V >/dev/null 2>&1; then
         YFLAGS="$YFLAGS -Wno-conflicts-sr"
     fi
+    YFLAGS="$YFLAGS -Wno-yacc"
 else
 sql=false
 fi