Fix various compatibility problems with newer GCC.

This is an amalgamation of these upstream commits:

  https://git.savannah.gnu.org/cgit/src-highlite.git/commit/?id=904949c9026cb772dc93fbe0947a252ef47127f4
  https://git.savannah.gnu.org/cgit/src-highlite.git/commit/?id=ab9fe5cb9b85c5afab94f2a7f4b6d7d473c14ee9

diff --git a/lib/srchilite/fileutil.cc b/lib/srchilite/fileutil.cc
index 59a6d64..963178c 100644
--- a/lib/srchilite/fileutil.cc
+++ b/lib/srchilite/fileutil.cc
@@ -48,7 +48,7 @@ void set_file_util_verbose(bool b) {
 // FIXME avoid using a global variable
 std::string start_path;
 
-string readFile(const string &fileName) throw (IOException) {
+string readFile(const string &fileName) {
     ifstream file(fileName.c_str());
 
     if (!file.is_open()) {
diff --git a/lib/srchilite/fileutil.h b/lib/srchilite/fileutil.h
index 7335a9b..042eb56 100644
--- a/lib/srchilite/fileutil.h
+++ b/lib/srchilite/fileutil.h
@@ -27,7 +27,7 @@ extern std::string start_path;
  * @return the contents of the file
  * @throw IOException
  */
-string readFile(const string &fileName) throw (IOException);
+string readFile(const string &fileName);
 
 //char *read_file(const string &fileName);
 
diff --git a/lib/tests/stdboosterror.h b/lib/tests/stdboosterror.h
index 568545b..d59bfa6 100644
--- a/lib/tests/stdboosterror.h
+++ b/lib/tests/stdboosterror.h
@@ -4,7 +4,7 @@
 #include <boost/regex/pattern_except.hpp>
 
 static boost::regex_error
-        std_boost_exception(boost::regex_error(boost::regex_constants::error_bad_pattern));
+        std_boost_exception = boost::regex_error(boost::regex_constants::error_bad_pattern);
 
 /**
  * returns the string representing a standard exception (which
diff --git a/lib/tests/test_wordtokenizer_main.cpp b/lib/tests/test_wordtokenizer_main.cpp
index 40e23b1..11ba389 100644
--- a/lib/tests/test_wordtokenizer_main.cpp
+++ b/lib/tests/test_wordtokenizer_main.cpp
@@ -11,6 +11,14 @@
 using namespace std;
 using namespace srchilite;
 
+/*
+ * We have to use 'std' namespaces because 'WordTokenizer::WordTokenizerResults::value_type'
+ * is an std::pair<std::string, std::string> in disguise. We have to place 'operator<<()'
+ * into the same namespace for ADL to work. Otherwise gcc-12 or clang-13 can't find the
+ * overload.
+ */
+namespace std {
+
 static ostream &operator <<(ostream &os, const WordTokenizer::WordTokenizerResults::value_type &);
 
 ostream &operator <<(ostream &os, const WordTokenizer::WordTokenizerResults::value_type &token) {
@@ -23,6 +31,8 @@ ostream &operator <<(ostream &os, const WordTokenizer::WordTokenizerResults::val
     return os;
 }
 
+}
+
 int main() {
     WordTokenizer::WordTokenizerResults tokens;
 4e133c61b42cf40ffa9707cf55&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-12-26 15:41:59 +0300'>2023-12-26</span></td><td><a href='/guix/commit/gnu/home/services/sound.scm?id=afdbf7f271529573397474fdb8f1c9d00dceba37'>gnu: home: Add home-pipewire service.</a><span class='msg-avail'>...<span class='msg-tooltip'>This adds a set of home Shepherd services which will start the required
services for a functional PipeWire setup.

* gnu/home/services/sound.scm (home-pipewire-shepherd-service,
home-wireplumber-shepherd-service, home-pipewire-shepherd-services,
home-pipewire-asoundrc, home-pipewire-xdg-configuration,
home-pipewire-pulseaudio-shepherd-service): New procedures.
(home-pipewire-service-type): New service type.
(home-pipewire-configuration): New struct.
(home-pipewire-disable-pulseaudio-auto-start): New variable.
* doc/guix.texi (Sound Home Services): Document it.

Change-Id: I99e0ae860de91d459c3c554ec5503bf35f785a2a
Signed-off-by: Oleg Pykhalov &lt;go.wigust@gmail.com&gt;
</span></span></td><td>Brian Cully</td></tr>
<tr><td><span title='2023-03-05 23:06:55 +0100'>2023-03-05</span></td><td><a href='/guix/commit/gnu/home/services/sound.scm?id=674d8933169e018efa3471e4eac52e5ea1e6afee'>home: services: Add 'pulseaudio-rtp-sink' and 'pulseaudio-rtp-source'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/home/services/sound.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (Sound Home Services): New section.
</span></span></td><td>Ludovic Courtès</td></tr>