GNU bug report logs - #21336
configure fails to detect C++ compiler on case-insensitive FS

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: "Daniel Macks" <dmacks <at> netspace.org>
To: bug-automake <at> gnu.org
Subject: configure fails to detect C++ compiler on case-insensitive FS
Date: Mon, 24 Aug 2015 06:12:32 -0400

Building automake-1.15 on OS X 10.10 on a case-insensitive filesystem, during ./configure I see:

checking whether cc understands -c and -o together... yes
checking for aCC... no
checking for FCC... no
checking for KCC... KCC
checking whether the C++ compiler works... no
configure: WARNING: C++ compiler cannot create executables
configure: tests requiring the C++ compiler will be skipped

I don't have "KCC" and my C++ compiler (at "c++" or "g++") is fine. I do however have /usr/bin/kcc, which AC_PROG_CXX finds when it looks for "KCC" on my filesystem:

# The list of C++ compilers here has been copied, pasted and edited
# from 'lib/autoconf/c.m4:AC_PROG_CXX' in the Autoconf distribution.
# Keep it in sync, or better again, find out a way to avoid this code
# duplication.
_AM_COMPILER_CAN_FAIL([AC_PROG_CXX(dnl
  [aCC $am_CC FCC KCC $am_RCC xlC_r xlC c++ cxx cc++ gpp g++])],
  [CXX=false; _AM_SKIP_COMP_TESTS([C++])])

But my "kcc" is some completely unrelated kerberos tool, so when AC_PROG_CXX tests to see whether it behaves as a compiler, it fails because it isn't a compiler, and the autoconf tests don't get as far as my actual compiler in the list of possibilities. This is the same situation as the now-fixed automake bugs #11893 and #10766, where looking for "CC" was finding "cc" on case-insensitive filesystems, so presumably the same solution could work. That is, only look for "KCC" if it's a case-sensitive FS.

This code from which this block is documented to derive is:

[g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC]

in autoconf git, so an alternate solution is to re-sync with that (notably, "KCC" is well after "c++" and "g++").

dan

--
Daniel Macks
dmacks <at> netspace.org

Message #10 received at 21336 <at> debbugs.gnu.org (full text, mbox):

From: Mike Frysinger <vapier <at> gentoo.org>
To: automake-patches <at> gnu.org
Cc: 21336 <at> debbugs.gnu.org
Subject: [PATCH] configure: handle KCC on case-insensitive filesystems
Date: Fri, 10 Dec 2021 01:55:58 -0500

This fixes https://debbugs.gnu.org/21336.  On macOS 10.10, there seems
to be a kerberos tool installed as "kcc" which breaks the check.

Also resync with latest autoconf which searches for clang++ too.

* configure.ac: Skip KCC check on case-insensitive filesystems.  Add
clang++ to the C++ search list.
---
 configure.ac | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index 5a00bd29e0a7..6be3ba7526b9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -444,11 +444,13 @@ AS_IF([test x"$GCC" = x"yes"], [am_CC_is_GNU=yes], [am_CC_is_GNU=no])
 # to a C++ compiler as expected (see automake bugs #11893 and #10766).
 # Similarly, we must avoid looking for 'RCC', as that can point to the
 # Qt4 "Resource Compiler": <http://doc.qt.digia.com/4.2/rcc.html>
+# And we avoid looking for 'KCC' as that can be a kerberos tool under
+# macOS systems.
 if test -f /bIn/rMdIr || test -f /uSr/bIn/rMdIr; then
   # Case-insensitive file system, don't look for CC.
-  am_CC= am_RCC=
+  am_CC= am_RCC= am_KCC=
 else
-  am_CC=CC am_RCC=RCC
+  am_CC=CC am_RCC=RCC am_KCC=KCC
 fi
 
 # The list of C++ compilers here has been copied, pasted and edited
@@ -456,7 +458,7 @@ fi
 # Keep it in sync, or better again, find out a way to avoid this code
 # duplication.
 _AM_COMPILER_CAN_FAIL([AC_PROG_CXX(dnl
-  [aCC $am_CC FCC KCC $am_RCC xlC_r xlC c++ cxx cc++ gpp g++])],
+  [aCC $am_CC FCC $am_KCC $am_RCC xlC_r xlC c++ cxx cc++ gpp g++ clang++])],
   [CXX=false; _AM_SKIP_COMP_TESTS([C++])])
 
 AS_IF([test x"$GXX" = x"yes"], [am_CXX_is_GNU=yes], [am_CXX_is_GNU=no])
-- 
2.33.0

Message #13 received at 21336 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Mike Frysinger <vapier <at> gentoo.org>
Cc: 21336 <at> debbugs.gnu.org, automake-patches <at> gnu.org
Subject: Re: [PATCH] configure: handle KCC on case-insensitive filesystems
Date: Sun, 12 Dec 2021 15:12:22 -0800

On Thu, Dec 9, 2021 at 10:56 PM Mike Frysinger <vapier <at> gentoo.org> wrote:
> This fixes https://debbugs.gnu.org/21336.  On macOS 10.10, there seems

Note that I still see kcc on 12.0.1

> to be a kerberos tool installed as "kcc" which breaks the check.
>
> Also resync with latest autoconf which searches for clang++ too.
>
> * configure.ac: Skip KCC check on case-insensitive filesystems.  Add
> clang++ to the C++ search list.

Modulo that log nit, this commit looks fine. Thanks!

Message #16 received at 21336 <at> debbugs.gnu.org (full text, mbox):

From: Karl Berry <karl <at> freefriends.org>
To: vapier <at> gentoo.org
Cc: 21336 <at> debbugs.gnu.org, automake-patches <at> gnu.org
Subject: Re: [PATCH] configure: handle KCC on case-insensitive filesystems
Date: Sun, 12 Dec 2021 19:08:52 -0700

    Subject: [PATCH] configure: handle KCC on case-insensitive filesystems

Pushed with doc tweak per Jim. Thanks.

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