Autoconf build: Fix the invalid test for '-Wno-deprecated-copy' flag

(shamelessly stolen from c26db650a1, which was for cmake build)

The original test was always successfull, even if the flag was invalid.

But checking for '-Wdeprecated-copy' instead yields to error if the
warning does not exist. Existent warning for 'deprecated-copy' implies
that 'no-deprecated-copy' also exist.

diff --git a/config/lyxinclude.m4 b/config/lyxinclude.m4
index a3f89a5ef412eb94ff8d8af2eb0b942d0c015085..0b41e21e5a818b999442af559714fc4437b12919 100644 (file)
--- a/config/lyxinclude.m4
+++ b/config/lyxinclude.m4
@@ -390,8 +390,8 @@ if test x$GXX = xyes; then
       dnl Shut off warning -Wdeprecated-copy, which triggers too much
       dnl note that g++ always accepts -Wno-xxx, even when -Wxxx is an error.
       AC_LANG_PUSH(C++)
-      AX_CHECK_COMPILE_FLAG([-Wno-deprecated-copy],
-       [AM_CXXFLAGS="$AM_CXXFLAGS -Wno-deprecated-copy"], [], [-Werror])
+      AX_CHECK_COMPILE_FLAG([-Wdeprecated-copy],
+       [AM_CXXFLAGS="$AM_CXXFLAGS -Wno-deprecated-copy"])
       AC_LANG_POP(C++)
     fi
   case $gxx_version in