configure.ac (cxx_compat_warn): Set if -Wc++-compat is supported.

* configure.ac (cxx_compat_warn): Set if -Wc++-compat is supported.
        * Makefile.in (CXX_COMPAT_WARN): Define.
        * configure: Regenerate.

cp/
        * Make-lang.in (cp-warn): Include CXX_COMPAT_WARN.
        * repo.c (extract_string, afgets): Use cast when converting from
        void *.

From-SVN: r110380

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2006-01-29  Gabriel Dos Reis  <gdr@integgrable-solutions.net>
+
+	* configure.ac (cxx_compat_warn): Set if -Wc++-compat is supported.
+	* Makefile.in (CXX_COMPAT_WARN): Define.
+	* configure: Regenerate.
+
 2006-01-29  Dorit Nuzman  <dorit@il.ibm.com>
 
 	PR tree-opt/25911

gcc/Makefile.in

@@ -173,12 +173,14 @@ coverageexts = .{gcda,gcno}
 # with other compilers.  This is partially controlled by configure in
 # stage1, as not all versions of gcc understand -Wno-long-long or
 # -Wno-variadic-macros.
+# CXX_COMPAT_WARN are C++ source compatibility warnings.
 LOOSE_WARN = -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes
 STRICT_WARN = @strict1_warn@
 WERROR_FLAGS = @WERROR@
 STRICT2_WARN = -pedantic -Wno-long-long -Wno-variadic-macros \
   -Wno-overlength-strings -Wold-style-definition -Wmissing-format-attribute \
   $(WERROR_FLAGS)
+CXX_COMPAT_WARN = @cxx_compat_warn@
 
 # This is set by --enable-checking.  The idea is to catch forgotten
 # "extern" tags in header files.

gcc/configure.ac

@@ -385,6 +385,23 @@ fi
 
 AC_SUBST(strict1_warn)
 
+# Get C++ compatibility warning flag, if supported.
+AC_CACHE_CHECK(
+  [whether ${CC} accepts -Wc++-compat],
+  [ac_cv_prog_cc_w_cxx_compat],
+  [save_CFLAGS="$CFLAGS"
+  CFLAGS="-Wc++-compat"
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
+                    [ac_cv_prog_cc_w_cxx_compat=yes],
+                    [ac_cv_prog_cc_w_cxx_compat=no])
+  CFLAGS="$save_CFLAGS"
+  ])
+if test x${ac_cv_prog_cc_w_cxx_compat} = xyes; then
+  cxx_compat_warn="-Wc++-compat"
+fi
+AC_SUBST(cxx_compat_warn)
+
+
 # If the native compiler is GCC, we can enable warnings even in stage1.  
 # That's useful for people building cross-compilers, or just running a
 # quick `make'.

gcc/cp/ChangeLog

@@ -1,3 +1,9 @@
+2006-01-29  Gabriel Dos Reis  <gdr@integrable-solutions.net>
+
+	* Make-lang.in (cp-warn): Include CXX_COMPAT_WARN.
+	* repo.c (extract_string, afgets): Use cast when converting from
+	void *. 
+
 2006-01-29  Gabriel Dos Reis  <gdr@integrable-solutions.net>
 
 	* call.c (alloc_conversion): Use cast when converting from void *.

gcc/cp/Make-lang.in

@@ -89,7 +89,7 @@ CXX_AND_OBJCXX_OBJS = cp/call.o cp/decl.o cp/expr.o cp/pt.o cp/typeck2.o \
 CXX_OBJS = cp/cp-lang.o stub-objc.o $(CXX_AND_OBJCXX_OBJS)
 
 # Use strict warnings for this front end.
-cp-warn = $(STRICT_WARN)
+cp-warn = $(STRICT_WARN) $(CXX_COMPAT_WARN)
 
 cc1plus-dummy$(exeext): $(CXX_OBJS) dummy-checksum.o $(BACKEND) $(LIBDEPS)
 	$(CC) $(ALL_CFLAGS) $(LDFLAGS) -o $@ \

gcc/cp/repo.c

@@ -85,7 +85,7 @@ extract_string (char **pp)
 
   obstack_1grow (&temporary_obstack, '\0');
   *pp = p;
-  return obstack_finish (&temporary_obstack);
+  return (char *) obstack_finish (&temporary_obstack);
 }
 
 static const char *
@@ -148,7 +148,7 @@ afgets (FILE *stream)
   if (obstack_object_size (&temporary_obstack) == 0)
     return NULL;
   obstack_1grow (&temporary_obstack, '\0');
-  return obstack_finish (&temporary_obstack);
+  return (char *) obstack_finish (&temporary_obstack);
 }
 
 void