# We need `config.h'.
CPPFLAGS="-I$abs_top_builddir/lib @CPPFLAGS@"
+# Don't just check if $POSIXLY_CORRECT is set, as Bash, when launched
+# as /bin/sh, sets the shell variable POSIXLY_CORRECT to y, but not
+# the environment variable.
+if env | grep '^POSIXLY_CORRECT=' >/dev/null; then
+ POSIXLY_CORRECT_IS_EXPORTED=true
+else
+ POSIXLY_CORRECT_IS_EXPORTED=false
+fi
+
## ------------------- ##
## C/C++ Compilation. ##
## ------------------- ##
CFLAGS="$NO_WERROR_CFLAGS @WERROR_CFLAGS@"
CXXFLAGS="$NO_WERROR_CXXFLAGS @WERROR_CXXFLAGS@"
+# C++ variants break strict aliasing analysis.
+NO_STRICT_ALIAS_CXXFLAGS='@NO_STRICT_ALIAS_CXXFLAGS@'
+
# If 'exit 77'; skip all C++ tests; otherwise ':'.
BISON_CXX_WORKS='@BISON_CXX_WORKS@'
+# Whether the compiler supports POSIXLY_CORRECT defined.
+: ${C_COMPILER_POSIXLY_CORRECT='@C_COMPILER_POSIXLY_CORRECT@'}
+: ${CXX_COMPILER_POSIXLY_CORRECT='@CXX_COMPILER_POSIXLY_CORRECT@'}
+
+if $POSIXLY_CORRECT_IS_EXPORTED; then
+ $C_COMPILER_POSIXLY_CORRECT ||
+ BISON_C_WORKS="as_fn_error 77 POSIXLY_CORRECT"
+ $CXX_COMPILER_POSIXLY_CORRECT ||
+ BISON_CXX_WORKS="as_fn_error 77 POSIXLY_CORRECT"
+fi
+
# Handle --compile-c-with-cxx here, once CXX and CXXFLAGS are known.
if "$at_arg_compile_c_with_cxx"; then
CC_IS_CXX=1
CC=$CXX
NO_WERROR_CFLAGS=$NO_WERROR_CXXFLAGS
CFLAGS=$CXXFLAGS
+ BISON_C_WORKS=$BISON_CXX_WORKS
else
CC_IS_CXX=0
fi