Merge branch 'maint'

* origin/maint:
  NEWS: warnings with clang
  warnings: avoid warnings from clang
  tests: no longer disable -O compiler options
  yacc.c: initialize yylval in pure-parser mode
  skeletons: style changes
  lalr1.cc: document exception safety
  lalr1.cc: check exception safety of error handling
  lalr1.cc: check (and fix) %printer exception safety
  lalr1.cc: check (and fix) %initial-action exception safety
  lalr1.cc: fix exception safety
  lalr1.cc: check exception safety.
  lalr1.cc: indentation fixes.
  lalr1.cc: don't leave macros define to nothing
  tests: minor improvements
  tests: use $PERL instead of perl
  build: look for Perl in configure.
  tests: fix sed portability issues
  tests: diff -u is not portable

Conflicts:
	data/c.m4
	data/glr.c
	data/lalr1.cc
	data/yacc.c
	doc/Makefile.am
	tests/atlocal.in
	tests/calc.at

tests/calc.at

@@ -503,14 +503,17 @@ AT_CHECK([cat stderr], 0, [expout])
 # Make sure we did not introduce bad spaces.  Checked here because all
 # the skeletons are (or should be) exercized here.
 m4_define([AT_CHECK_SPACES],
-[# No initial empty lines.
-AT_CHECK([sed -ne '/./q;=;p;' $1])
-# No trailing spaces.
-AT_CHECK([sed -ne '/[ ]$/{=;p;}' $1])
-# No tabulations.
-AT_CHECK([sed -ne '/[	]/{=;p;}' $1])
-# No final empty lines.
-AT_CHECK([sed -ne '${/^$/{=;p;};}' $1])
+[AT_CHECK([$PERL -ne '
+  chomp;
+  print "$.: {$_}\n"
+    if (# No starting/ending empty lines.
+        (eof || $. == 1) && /^\s*$/
+        # No trailing space.
+        || /\s$/
+        # No tabs.
+        || /\t/
+        )' $1
+])dnl
 ])