Build ICU support by default.

Discussion: https://postgr.es/m/82c4c816-06f6-d3e3-ba02-fca4a5cef065%40enterprisedb.com
Reviewed-by: Peter Eisentraut

.cirrus.yml

@@ -776,6 +776,7 @@ task:
       time ./configure \
         --host=x86_64-w64-mingw32 \
         --enable-cassert \
+        --without-icu \
         CC="ccache x86_64-w64-mingw32-gcc" \
         CXX="ccache x86_64-w64-mingw32-g++"
       make -s -j${BUILD_JOBS} clean

configure

@@ -1558,7 +1558,7 @@ Optional Packages:
                           set WAL block size in kB [8]
   --with-CC=CMD           set compiler (deprecated)
   --with-llvm             build with LLVM based JIT support
-  --with-icu              build with ICU support
+  --without-icu           build without ICU support
   --with-tcl              build Tcl modules (PL/Tcl)
   --with-tclconfig=DIR    tclConfig.sh is in DIR
   --with-perl             build Perl modules (PL/Perl)
@@ -8401,7 +8401,9 @@ $as_echo "#define USE_ICU 1" >>confdefs.h
   esac
 
 else
-  with_icu=no
+  with_icu=yes
+
+$as_echo "#define USE_ICU 1" >>confdefs.h
 
 fi
 
@@ -8470,31 +8472,17 @@ fi
 	# Put the nasty error message in config.log where it belongs
 	echo "$ICU_PKG_ERRORS" >&5
 
-	as_fn_error $? "Package requirements (icu-uc icu-i18n) were not met:
-
-$ICU_PKG_ERRORS
-
-Consider adjusting the PKG_CONFIG_PATH environment variable if you
-installed software in a non-standard prefix.
-
-Alternatively, you may set the environment variables ICU_CFLAGS
-and ICU_LIBS to avoid the need to call pkg-config.
-See the pkg-config man page for more details." "$LINENO" 5
+	as_fn_error $? "ICU library not found
+If you have ICU already installed, see config.log for details on the
+failure.  It is possible the compiler isn't looking in the proper directory.
+Use --without-icu to disable ICU support." "$LINENO" 5
 elif test $pkg_failed = untried; then
         { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-	{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-as_fn_error $? "The pkg-config script could not be found or is too old.  Make sure it
-is in your PATH or set the PKG_CONFIG environment variable to the full
-path to pkg-config.
-
-Alternatively, you may set the environment variables ICU_CFLAGS
-and ICU_LIBS to avoid the need to call pkg-config.
-See the pkg-config man page for more details.
-
-To get pkg-config, see <http://pkg-config.freedesktop.org/>.
-See \`config.log' for more details" "$LINENO" 5; }
+	as_fn_error $? "ICU library not found
+If you have ICU already installed, see config.log for details on the
+failure.  It is possible the compiler isn't looking in the proper directory.
+Use --without-icu to disable ICU support." "$LINENO" 5
 else
 	ICU_CFLAGS=$pkg_cv_ICU_CFLAGS
 	ICU_LIBS=$pkg_cv_ICU_LIBS

configure.ac

@@ -853,13 +853,17 @@ AC_SUBST(enable_thread_safety)
 # ICU
 #
 AC_MSG_CHECKING([whether to build with ICU support])
-PGAC_ARG_BOOL(with, icu, no, [build with ICU support],
+PGAC_ARG_BOOL(with, icu, yes, [build without ICU support],
               [AC_DEFINE([USE_ICU], 1, [Define to build with ICU support. (--with-icu)])])
 AC_MSG_RESULT([$with_icu])
 AC_SUBST(with_icu)
 
 if test "$with_icu" = yes; then
-  PKG_CHECK_MODULES(ICU, icu-uc icu-i18n)
+  PKG_CHECK_MODULES(ICU, icu-uc icu-i18n, [],
+    [AC_MSG_ERROR([ICU library not found
+If you have ICU already installed, see config.log for details on the
+failure.  It is possible the compiler isn't looking in the proper directory.
+Use --without-icu to disable ICU support.])])
 fi
 
 #

doc/src/sgml/installation.sgml

@@ -146,6 +146,35 @@ documentation.  See standalone-profile.xsl for details.
       <application>pg_restore</application>.
      </para>
     </listitem>
+
+    <listitem>
+     <para>
+      The ICU locale provider (see <xref linkend="locale-providers"/>) is used by default. If you don't want to use it then you must specify the <option>--without-icu</option> option to <filename>configure</filename>. Using this option disables support for ICU collation features (see <xref linkend="collation"/>).
+     </para>
+     <para>
+      ICU support requires the <productname>ICU4C</productname> package to be
+      installed.  The minimum required version of
+      <productname>ICU4C</productname> is currently 4.2.
+     </para>
+
+     <para>
+      By default,
+      <productname>pkg-config</productname><indexterm><primary>pkg-config</primary></indexterm>
+      will be used to find the required compilation options.  This is
+      supported for <productname>ICU4C</productname> version 4.6 and later.
+      For older versions, or if <productname>pkg-config</productname> is not
+      available, the variables <envar>ICU_CFLAGS</envar> and
+      <envar>ICU_LIBS</envar> can be specified to
+      <filename>configure</filename>, like in this example:
+<programlisting>
+./configure ... ICU_CFLAGS='-I/some/where/include' ICU_LIBS='-L/some/where/lib -licui18n -licuuc -licudata'
+</programlisting>
+      (If <productname>ICU4C</productname> is in the default search path
+      for the compiler, then you still need to specify nonempty strings in
+      order to avoid use of <productname>pkg-config</productname>, for
+      example, <literal>ICU_CFLAGS=' '</literal>.)
+     </para>
+    </listitem>
    </itemizedlist>
   </para>
 
@@ -926,40 +955,6 @@ build-postgresql:
        </listitem>
       </varlistentry>
 
-      <varlistentry id="configure-option-with-icu">
-       <term><option>--with-icu</option></term>
-       <listitem>
-        <para>
-         Build with support for
-         the <productname>ICU</productname><indexterm><primary>ICU</primary></indexterm>
-         library, enabling use of ICU collation
-         features<phrase condition="standalone-ignore"> (see
-         <xref linkend="collation"/>)</phrase>.
-         This requires the <productname>ICU4C</productname> package
-         to be installed.  The minimum required version
-         of <productname>ICU4C</productname> is currently 4.2.
-        </para>
-
-        <para>
-         By default,
-         <productname>pkg-config</productname><indexterm><primary>pkg-config</primary></indexterm>
-         will be used to find the required compilation options.  This is
-         supported for <productname>ICU4C</productname> version 4.6 and later.
-         For older versions, or if <productname>pkg-config</productname> is
-         not available, the variables <envar>ICU_CFLAGS</envar>
-         and <envar>ICU_LIBS</envar> can be specified
-         to <filename>configure</filename>, like in this example:
-<programlisting>
-./configure ... --with-icu ICU_CFLAGS='-I/some/where/include' ICU_LIBS='-L/some/where/lib -licui18n -licuuc -licudata'
-</programlisting>
-         (If <productname>ICU4C</productname> is in the default search path
-         for the compiler, then you still need to specify nonempty strings in
-         order to avoid use of <productname>pkg-config</productname>, for
-         example, <literal>ICU_CFLAGS=' '</literal>.)
-        </para>
-       </listitem>
-      </varlistentry>
-
       <varlistentry id="configure-with-llvm">
        <term><option>--with-llvm</option></term>
        <listitem>
@@ -1231,6 +1226,19 @@ build-postgresql:
 
      <variablelist>
 
+      <varlistentry id="configure-option-without-icu">
+       <term><option>--without-icu</option></term>
+       <listitem>
+        <para>
+         Build without support for the
+         <productname>ICU</productname><indexterm><primary>ICU</primary></indexterm>
+         library, disabling the use of ICU collation features<phrase
+         condition="standalone-ignore"> (see <xref
+         linkend="collation"/>)</phrase>.
+        </para>
+       </listitem>
+      </varlistentry>
+
       <varlistentry id="configure-option-without-readline">
        <term><option>--without-readline</option></term>
        <listitem>