Use -Wshadow=local if supported

autofiles.sums

@@ -1,4 +1,4 @@
-c9b8555013e70c93572e0be5f5c7c03c6b7e0680de4870010945357a02909eaa  configure.ac
+be950d7be6b0aa2c9c926ac43ca9478ef864b1cb2c8184fd393c9ce4c0972bcc  configure.ac
 d3f9ee6f6f0846888d9a10fd3dad2e4b1258be84205426cf04d7cef02d61dad7  aclocal.m4
 b0ce6d1dba8effa47d25154b2bb56eddafc997254a0f3f903cf9b6abffc03616  libqpdf/qpdf/qpdf-config.h.in
 5297971a0ef90bcd5563eb3f7127a032bb76d3ae2af7258bf13479caf8983a60  m4/ax_cxx_compile_stdcxx.m4

configure

@@ -785,7 +785,6 @@ enable_largefile
 enable_ld_version_script
 with_buildrules
 enable_werror
-enable_int_warnings
 enable_implicit_crypto
 enable_crypto_native
 enable_crypto_openssl
@@ -1473,8 +1472,6 @@ Optional Features:
   --enable-ld-version-script
                           enable linker version script (default is enabled)
   --enable-werror         whether to treat warnings as errors (default is no)
-  --enable-int-warnings   whether to turn on integer type warnings (default is
-                          yes)
   --enable-implicit-crypto
                           whether to enable available crypto providers that
                           are not explicitly requested; true by default
@@ -17631,26 +17628,70 @@ if test "$BUILDRULES" = "msvc"; then
 else
    try_flags="-Wconversion -Wsign-conversion"
 fi
+oCFLAGS=$CFLAGS
+CFLAGS="$CFLAGS $try_flags"
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for whether to use $try_flags" >&5
 $as_echo_n "checking for whether to use $try_flags... " >&6; }
-# Check whether --enable-int-warnings was given.
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-if test "${enable_int_warnings+set}" = set; then :
+/* end confdefs.h.  */
-  enableval=$enable_int_warnings; if test "$enableval" = "yes"; then
-      qpdf_INT_WARNINGS=1;
-    else
-      qpdf_INT_WARNINGS=0;
-    fi
-else
-  qpdf_INT_WARNINGS=1
-fi
 
+int
+main ()
+{
+int a = 1; int b = a; a = b;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  qpdf_INT_WARNINGS=1
+else
+  qpdf_INT_WARNINGS=0
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 if test "$qpdf_INT_WARNINGS" = "1"; then
    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
-   WFLAGS="$WFLAGS $try_flags"
+   CXXFLAGS="$CXXFLAGS $try_flags"
 else
    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
+   CFLAGS=$oCFLAGS
+fi
+
+if test "$BUILDRULES" != "msvc"; then
+   try_flags="-Wshadow=local"
+   oCFLAGS=$CFLAGS
+   CFLAGS="$CFLAGS $try_flags -Werror"
+   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for whether to use $try_flags" >&5
+$as_echo_n "checking for whether to use $try_flags... " >&6; }
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+int a = 1; int b = a; a = b;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  qpdf_SHADOW_WARNINGS=1
+else
+  qpdf_SHADOW_WARNINGS=0
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+   if test "$qpdf_SHADOW_WARNINGS" = "1"; then
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+      CFLAGS="$oCFLAGS $try_flags"
+      CXXFLAGS="$CXXFLAGS $try_flags"
+   else
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+      CFLAGS=$oCFLAGS
+   fi
 fi
 
 

configure.ac

@@ -475,20 +475,34 @@ if test "$BUILDRULES" = "msvc"; then
 else
    try_flags="-Wconversion -Wsign-conversion"
 fi
+oCFLAGS=$CFLAGS
+CFLAGS="$CFLAGS $try_flags"
 AC_MSG_CHECKING(for whether to use $try_flags)
-AC_ARG_ENABLE(int-warnings,
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[int a = 1; int b = a; a = b;]])],
-   AS_HELP_STRING([--enable-int-warnings],
+                  [qpdf_INT_WARNINGS=1],[qpdf_INT_WARNINGS=0])
-                  [whether to turn on integer type warnings (default is yes)]),
-   [if test "$enableval" = "yes"; then
-      qpdf_INT_WARNINGS=1;
-    else
-      qpdf_INT_WARNINGS=0;
-    fi], [qpdf_INT_WARNINGS=1])
 if test "$qpdf_INT_WARNINGS" = "1"; then
    AC_MSG_RESULT(yes)
-   WFLAGS="$WFLAGS $try_flags"
+   CXXFLAGS="$CXXFLAGS $try_flags"
 else
    AC_MSG_RESULT(no)
+   CFLAGS=$oCFLAGS
+fi
+
+if test "$BUILDRULES" != "msvc"; then
+   try_flags="-Wshadow=local"
+   oCFLAGS=$CFLAGS
+   CFLAGS="$CFLAGS $try_flags -Werror"
+   AC_MSG_CHECKING(for whether to use $try_flags)
+   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[int a = 1; int b = a; a = b;]])],
+                     [qpdf_SHADOW_WARNINGS=1],[qpdf_SHADOW_WARNINGS=0])
+   if test "$qpdf_SHADOW_WARNINGS" = "1"; then
+      AC_MSG_RESULT(yes)
+      CFLAGS="$oCFLAGS $try_flags"
+      CXXFLAGS="$CXXFLAGS $try_flags"
+   else
+      AC_MSG_RESULT(no)
+      CFLAGS=$oCFLAGS
+   fi
 fi
 
 AC_SUBST(WINDOWS_WMAIN_XLINK_FLAGS)