diff --git a/ext/odbc/config.m4 b/ext/odbc/config.m4
index 96262ecf40630..b754ddd4e6d7c 100644
--- a/ext/odbc/config.m4
+++ b/ext/odbc/config.m4
@@ -14,22 +14,26 @@ AC_DEFUN([PHP_ODBC_FIND_SOLID_LIBS],[
     HP-UX) ac_solid_os=h9x;; # h1x for hpux11, h0x for hpux10
     Linux)
       if ldd -v /bin/sh | grep GLIBC > /dev/null; then
-        AC_DEFINE(SS_LINUX,1,[Needed in sqlunix.h ])
         ac_solid_os=l2x
       else
-        AC_DEFINE(SS_LINUX,1,[Needed in sqlunix.h ])
         ac_solid_os=lux
-      fi;;
+      fi
+      AC_DEFINE([SS_LINUX], [1],
+        [Define to 1 to be able to use the obsolete <sqlunix.h> header file on
+        some Linux systems.])
+      ;;
     SunOS)
       ac_solid_os=ssx;; # should we deal with SunOS 4?
     FreeBSD)
       if test `expr $ac_solid_uname_r : '\(.\)'` -gt "2"; then
-        AC_DEFINE(SS_FBX,1,[Needed in sqlunix.h for wchar defs ])
         ac_solid_os=fex
       else
-        AC_DEFINE(SS_FBX,1,[Needed in sqlunix.h for wchar defs ])
         ac_solid_os=fbx
-      fi;;
+      fi
+      AC_DEFINE([SS_FBX], [1],
+        [Define to 1 to be able to use the wchar defs in the obsolete
+        <sqlunix.h> header file on some FreeBSD systems.])
+      ;;
   esac
 
   if test -f $1/soc${ac_solid_os}35.a; then
@@ -119,7 +123,8 @@ PHP_ARG_WITH([adabas],,
     ODBC_TYPE=adabas
     ODBC_INCDIR=$PHP_ADABAS/incl
     PHP_ODBC_CHECK_HEADER(sqlext.h)
-    AC_DEFINE(HAVE_ADABAS,1,[ ])
+    AC_DEFINE([HAVE_ADABAS], [1],
+      [Define to 1 if the odbc extension uses the Adabas D.])
     AC_MSG_RESULT([$ext_output])
   else
     AC_MSG_RESULT([no])
@@ -140,7 +145,8 @@ PHP_ARG_WITH([sapdb],,
     PHP_ADD_LIBPATH([$PHP_SAPDB/$PHP_LIBDIR])
     PHP_ADD_LIBRARY([sqlod])
     ODBC_TYPE=sapdb
-    AC_DEFINE(HAVE_SAPDB,1,[ ])
+    AC_DEFINE([HAVE_SAPDB], [1],
+      [Define to 1 if the odbc extension uses the SAP DB.])
     AC_MSG_RESULT([$ext_output])
   else
     AC_MSG_RESULT([no])
@@ -162,11 +168,12 @@ PHP_ARG_WITH([solid],,
     ODBC_CFLAGS=-I$ODBC_INCDIR
     ODBC_TYPE=solid
     if test -f $ODBC_LIBDIR/soc*35.a; then
-      AC_DEFINE(HAVE_SOLID_35,1,[ ])
+      AC_DEFINE([HAVE_SOLID_35], [1], [Define to 1 if Solid DB 3.5 is used.])
     elif test -f $ODBC_LIBDIR/scl*30.a; then
-      AC_DEFINE(HAVE_SOLID_30,1,[ ])
+      AC_DEFINE([HAVE_SOLID_30], [1], [Define to 1 if Solid DB 3.0 is used.])
     elif test -f $ODBC_LIBDIR/scl*23.a; then
-      AC_DEFINE(HAVE_SOLID,1,[ ])
+      AC_DEFINE([HAVE_SOLID], [1],
+        [Define to 1 if the odbc extension uses the Solid DB.])
     fi
     AC_MSG_RESULT([$ext_output])
     PHP_ODBC_FIND_SOLID_LIBS($ODBC_LIBDIR)
@@ -198,7 +205,8 @@ PHP_ARG_WITH([ibm-db2],,
     ODBC_LIBS=-ldb2
 
     PHP_TEST_BUILD([SQLExecute], [
-      AC_DEFINE(HAVE_IBMDB2,1,[ ])
+      AC_DEFINE([HAVE_IBMDB2], [1],
+        [Define to 1 if the odbc extension uses the IBM DB2.])
       AC_MSG_RESULT([$ext_output])
     ], [
       AC_MSG_RESULT([no])
@@ -232,7 +240,8 @@ PHP_ARG_WITH([empress],,
     ODBC_CFLAGS=-I$ODBC_INCDIR
     ODBC_LFLAGS=-L$ODBC_LIBDIR
     ODBC_TYPE=empress
-    AC_DEFINE(HAVE_EMPRESS,1,[ ])
+    AC_DEFINE([HAVE_EMPRESS], [1],
+      [Define to 1 if the odbc extension uses the Empress.])
     AC_MSG_RESULT([$ext_output])
     PHP_ODBC_FIND_EMPRESS_LIBS($ODBC_LIBDIR)
   else
@@ -274,7 +283,8 @@ PHP_ARG_WITH([empress-bcs],,
     done
     ODBC_LIBS="-lempphpbcs -lms -lmscfg -lbasic -lbasic_os -lnlscstab -lnlsmsgtab -lm -ldl -lcrypt"
     ODBC_TYPE=empress-bcs
-    AC_DEFINE(HAVE_EMPRESS,1,[ ])
+    AC_DEFINE([HAVE_EMPRESS], [1],
+      [Define to 1 if the odbc extension uses the Empress.])
     AC_MSG_RESULT([$ext_output])
     PHP_ODBC_FIND_EMPRESS_BCS_LIBS($ODBC_LIBDIR)
   else
@@ -303,7 +313,8 @@ PHP_ARG_WITH([custom-odbc],,
     ODBC_CFLAGS=-I$ODBC_INCDIR
     ODBC_LIBS=$CUSTOM_ODBC_LIBS
     ODBC_TYPE=custom-odbc
-    AC_DEFINE(HAVE_CODBC,1,[ ])
+    AC_DEFINE([HAVE_CODBC], [1],
+      [Define to 1 if the odbc extension uses custom ODBC installation.])
     AC_MSG_RESULT([$ext_output])
   else
     AC_MSG_RESULT([no])
@@ -321,7 +332,8 @@ PHP_ARG_WITH([iodbc],,
     PKG_CHECK_MODULES([ODBC], [libiodbc])
     PHP_EVAL_INCLINE([$ODBC_CFLAGS])
     ODBC_TYPE=iodbc
-    AC_DEFINE(HAVE_IODBC,1,[ ])
+    AC_DEFINE([HAVE_IODBC], [1],
+      [Define to 1 if the odbc extension uses the iODBC.])
   else
     AC_MSG_RESULT([no])
   fi
@@ -343,7 +355,8 @@ PHP_ARG_WITH([esoob],,
     ODBC_CFLAGS=-I$ODBC_INCDIR
     ODBC_LIBS=-lesoobclient
     ODBC_TYPE=esoob
-    AC_DEFINE(HAVE_ESOOB,1,[ ])
+    AC_DEFINE([HAVE_ESOOB], [1],
+      [Define to 1 if the odbc extension uses the Easysoft OOB.])
     AC_MSG_RESULT([$ext_output])
   else
     AC_MSG_RESULT([no])
@@ -372,7 +385,8 @@ PHP_ARG_WITH([unixODBC],,
       AC_MSG_RESULT([yes in $PHP_UNIXODBC])
     fi
     ODBC_TYPE=unixODBC
-    AC_DEFINE(HAVE_UNIXODBC,1,[ ])
+    AC_DEFINE([HAVE_UNIXODBC], [1],
+      [Define to 1 if the odbc extension uses the unixODBC.])
   else
     AC_MSG_RESULT([no])
   fi
@@ -413,7 +427,8 @@ PHP_ARG_WITH([dbmaker],,
     ODBC_LIBS="-ldmapic -lc"
     ODBC_TYPE=dbmaker
 
-    AC_DEFINE(HAVE_DBMAKER,1,[Whether you want DBMaker])
+    AC_DEFINE([HAVE_DBMAKER], [1],
+      [Define to 1 if the odbc extension uses the DBMaker.])
 
     if test "$ext_shared" = "yes"; then
       AC_MSG_RESULT([yes (shared)])
@@ -430,13 +445,11 @@ PHP_ARG_WITH([dbmaker],,
   fi
 fi
 
-if test "no" != "$PHP_ODBCVER"; then
-  if test "$PHP_ODBCVER" != "0"; then
-    AC_DEFINE_UNQUOTED(ODBCVER, $PHP_ODBCVER, [ The highest supported ODBC version ])
-  fi
-else
-  AC_DEFINE(ODBCVER, 0x0350, [ The highest supported ODBC version ])
-fi
+AH_TEMPLATE([ODBCVER], [The highest supported ODBC version.])
+AS_VAR_IF([PHP_ODBCVER], [no],
+  [AC_DEFINE([ODBCVER], [0x0350])],
+  [AS_VAR_IF([PHP_ODBCVER], [0],,
+    [AC_DEFINE_UNQUOTED([ODBCVER], [$PHP_ODBCVER])])])
 
 dnl Extension setup
 if test -n "$ODBC_TYPE"; then
diff --git a/ext/odbc/config.w32 b/ext/odbc/config.w32
index a5740bdaa6cdc..a170ed05208ac 100644
--- a/ext/odbc/config.w32
+++ b/ext/odbc/config.w32
@@ -10,9 +10,9 @@ if (PHP_ODBC == "yes") {
 		EXTENSION("odbc", "php_odbc.c odbc_utils.c", PHP_ODBC_SHARED, "/DZEND_ENABLE_STATIC_TSRMLS_CACHE=1");
 		AC_DEFINE("HAVE_UODBC", 1, "Define to 1 if the PHP extension 'odbc' is available.");
 		if ("no" == PHP_ODBCVER) {
-			AC_DEFINE("ODBCVER", "0x0350", "The highest supported ODBC version", false);
+			AC_DEFINE("ODBCVER", "0x0350", "The highest supported ODBC version.", false);
 		} else if ("0" != PHP_ODBCVER) {
-			AC_DEFINE("ODBCVER", PHP_ODBCVER, "The highest supported ODBC version", false);
+			AC_DEFINE("ODBCVER", PHP_ODBCVER, "The highest supported ODBC version.", false);
 		}
 	} else {
 		WARNING("odbc support can't be enabled, libraries or header are missing (SDK)")