Enable many more compiler warnings

* m4/manywarnings.m4m, m4/warnings.m4: Import GNULIB warnings
  modules
* m4/spice-compile-warnings.m4: Define SPICE_COMPILE_WARNINGS
* configure.ac: Replace compile warning check with a call to
  SPICE_COMPILE_WARNINGS
* client/Makefile.am: Use WARN_CXXFLAGS instead of WARN_CFLAGS

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/m4/warnings.m4 b/m4/warnings.m4
new file mode 100644
index 00000000..69d05a67
--- /dev/null
+++ b/m4/warnings.m4
@@ -0,0 +1,37 @@
+# warnings.m4 serial 5
+dnl Copyright (C) 2008-2012 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson
+
+# gl_AS_VAR_APPEND(VAR, VALUE)
+# ----------------------------
+# Provide the functionality of AS_VAR_APPEND if Autoconf does not have it.
+m4_ifdef([AS_VAR_APPEND],
+[m4_copy([AS_VAR_APPEND], [gl_AS_VAR_APPEND])],
+[m4_define([gl_AS_VAR_APPEND],
+[AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
+
+# gl_WARN_ADD(PARAMETER, [VARIABLE = WARN_CFLAGS])
+# ------------------------------------------------
+# Adds parameter to WARN_CFLAGS if the compiler supports it.  For example,
+# gl_WARN_ADD([-Wparentheses]).
+AC_DEFUN([gl_WARN_ADD],
+dnl FIXME: gl_Warn must be used unquoted until we can assume
+dnl autoconf 2.64 or newer.
+[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_$1])dnl
+AC_CACHE_CHECK([whether compiler handles $1], m4_defn([gl_Warn]), [
+  gl_save_CPPFLAGS="$CPPFLAGS"
+  CPPFLAGS="${CPPFLAGS} $1"
+  AC_PREPROC_IFELSE([AC_LANG_PROGRAM([])],
+                    [AS_VAR_SET(gl_Warn, [yes])],
+                    [AS_VAR_SET(gl_Warn, [no])])
+  CPPFLAGS="$gl_save_CPPFLAGS"
+])
+AS_VAR_IF(gl_Warn, [yes],
+  [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])])
+AS_VAR_POPDEF([gl_Warn])dnl
+m4_ifval([$2], [AS_LITERAL_IF([$2], [AC_SUBST([$2])], [])])dnl
+])