configure.ac: fix grpc build

Similar to the previous "configure.ac: fix grpc build" commit:
Google bumped it's compiler requirements again [1], hence the c++ version needs to be adjusted to c++17 to be able to build with the latest grpc versions.

[1] https://github.com/google/oss-policies-info/blob/a5e3ed43d45ad615a20201cea8f7282f595555da/foundational-cxx-support-matrix.md

Signed-off-by: Michael Nosthoff <buildroot@heine.tech>

diff --git a/configure.ac b/configure.ac
index 8aa03fce63e96c06aff1f13fe3280ffe6418e8bd..eb6cbbc5d50e94c11f4be10bb237b04c555b21fa 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -2844,20 +2844,20 @@ PKG_CHECK_MODULES([GRPCPP], [grpc++],
 fi
 
 if test "x$withval" != "xno"; then
-  AC_MSG_CHECKING([whether $CXX accepts -std=c++14])
-  if test_cxx_flags -std=c++14; then
+  AC_MSG_CHECKING([whether $CXX accepts -std=c++17])
+  if test_cxx_flags -std=c++17; then
     AC_MSG_RESULT([yes])
   else
     AC_MSG_RESULT([no])
-    with_libgrpcpp="no (requires C++14 support)"
-    with_libprotobuf="no (<absl/base/policy_checks.h> requires C++14 support)"
+    with_libgrpcpp="no (requires C++17 support)"
+    with_libprotobuf="no (<absl/base/policy_checks.h> requires C++17 support)"
   fi
 fi
 
 if test "x$with_libgrpcpp" = "xyes"; then
   AC_LANG_PUSH(C++)
   SAVE_CPPFLAGS="$CPPFLAGS"
-  CPPFLAGS="-std=c++14 $with_libgrpcpp_cppflags $GRPCPP_CFLAGS $CPPFLAGS"
+  CPPFLAGS="-std=c++17 $with_libgrpcpp_cppflags $GRPCPP_CFLAGS $CPPFLAGS"
   AC_CHECK_HEADERS([grpc++/grpc++.h],
     [with_libgrpcpp="yes"],
     [with_libgrpcpp="no (<grpc++/grpc++.h> not found)"]
@@ -2871,7 +2871,7 @@ if test "x$with_libgrpcpp" = "xyes"; then
   SAVE_CPPFLAGS="$CPPFLAGS"
   SAVE_LDFLAGS="$LDFLAGS"
   SAVE_LIBS="$LIBS"
-  CPPFLAGS="-std=c++14 $with_libgrpcpp_cppflags $GRPCPP_CFLAGS $CPPFLAGS"
+  CPPFLAGS="-std=c++17 $with_libgrpcpp_cppflags $GRPCPP_CFLAGS $CPPFLAGS"
   LDFLAGS="$with_libgrpcpp_ldflags"
   if test "x$GRPCPP_LIBS" = "x"; then
     LIBS="-lgrpc++"
@@ -2899,7 +2899,7 @@ if test "x$with_libgrpcpp" = "xyes"; then
   AC_LANG_POP(C++)
 fi
 
-BUILD_WITH_LIBGRPCPP_CPPFLAGS="-std=c++14 $with_libgrpcpp_cppflags $GRPCPP_CFLAGS"
+BUILD_WITH_LIBGRPCPP_CPPFLAGS="-std=c++17 $with_libgrpcpp_cppflags $GRPCPP_CFLAGS"
 BUILD_WITH_LIBGRPCPP_LDFLAGS="$with_libgrpcpp_ldflags"
 BUILD_WITH_LIBGRPCPP_LIBS="$GRPCPP_LIBS"
 AC_SUBST([BUILD_WITH_LIBGRPCPP_CPPFLAGS])
@@ -4843,7 +4843,7 @@ if test "x$withval" != "xno"; then
   AC_CHECK_LIB([protobuf], [main],
     [
       SAVE_CPPFLAGS="$CPPFLAGS"
-      CPPFLAGS="-std=c++14 $with_libprotobuf_cppflags $PROTOBUF_CFLAGS"
+      CPPFLAGS="-std=c++17 $with_libprotobuf_cppflags $PROTOBUF_CFLAGS"
       if test "x$PROTOBUF_LIBS" = "x"
       then
         PROTOBUF_LIBS="-lprotobuf"