1 files changed, 27 insertions, 1 deletions
diff --git a/configure b/configure
index 6ef68942..c6552968 100755
--- a/configure
+++ b/configure
@@ -128,7 +128,7 @@ yacc_given=${yacc+y}
 yacc=${yacc-'$(cross)$(tool_prefix)$(yaccname)'}
 nm=${nm-'$(cross)$(tool_prefix)nm'}
 opt_flags=${opt_flags--O2}
-lang_flags=${lang_flags--ansi -D_XOPEN_SOURCE}
+lang_flags=${lang_flags--ansi -D_XOPEN_SOURCE=2}
 diag_flags=${diag_flags--Wall -Wmissing-prototypes -Wstrict-prototypes}
 debug_flags=${debug_flags--g}
 inline=${inline-}
@@ -666,6 +666,32 @@ done
 printf "done\n"
 
 #
+# Check for annoying warnings from ctype.h macros
+#
+
+printf "Checking for annoying warnings from <ctype.h> macros ... "
+
+cat > conftest.c <<!
+#include <ctype.h>
+
+int main(void)
+{
+  char x = '3';
+  return isdigit(x);
+}
+!
+if ! $make EXTRA_FLAGS=-Werror conftest > conftest.err 2>&1 || ! [ -x conftest ] ; then
+  printf "present\n"
+  cat >> config.h <<!
+$(for x in isalpha isupper islower isdigit isxdigit isalnum isspace \
+           ispunct isprint isgraph iscntrl isblank ; do \
+    printf "#undef %s\n" $x ; done)
+!
+else
+  printf "absent\n"
+fi
+
+#
 # Check what kind of C type we have for integers wider than long,
 # if any.
 #