URL:
<https://savannah.gnu.org/support/?110451>
Summary: autoconf 2.71 generated configure file does not
enable C compiler flag for C99 on Solaris 10
Project: Autoconf
Submitted by: haible
Submitted on: Sat 27 Feb 2021 09:05:03 PM CET
Category: None
Priority: 5 - Normal
Severity: 3 - Normal
Status: None
Privacy: Public
Assigned to: None
Originator Email:
Open/Closed: Open
Discussion Lock: Any
Operating System: Solaris
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Details:
This is a regression in autoconf 2.71, compared to autoconf 2.69.
Find attached two tarballs, hello-c-2.69.tar.gz (generated with autoconf 2.69)
and hello-c-2.71.tar.gz (generated with autoconf 2.71). They contain the same
source code, except for the version number in configure.ac. In particular,
they contain
- in configure.ac, an AC_PROG_CC_C99 invocation,
- in hello.c: code that requires C99.
The commands to regenerate everything in these tarballs is:
aclocal -I m4
autoconf
autoheader
automake -a -c
rm -rf autom4te.cache
On Solaris 10, I'm using CC="cc -O". This compiler is not C99 compliant, but
it accepts the option '-xc99' which makes it C99 compliant.
Both packages ought to exhibit the same behaviour, but they don't:
* The hello-c-2.69 package compiles fine.
./configure prints:
checking whether we are using the GNU C compiler... no
checking whether cc -O accepts -g... yes
checking for cc -O option to accept ISO C89... none needed
checking whether cc -O understands -c and -o together... yes
checking whether make supports the include directive... yes (GNU style)
checking dependency style of cc -O... none
checking for cc -O option to accept ISO C99... -D_STDC_C99=
The option '-D_STDC_C99=' is probably not entirely equivalent to '-xc99', but
it is good enough: The compilation command
cc -O -D_STDC_C99= -DHAVE_CONFIG_H -I. -I.. -g -c -o hello.o ../hello.c
succeeds.
* The hello-c-2.71 package does not build.
./configure prints:
checking whether the compiler supports GNU C... no
checking whether cc -O accepts -g... yes
checking for cc -O option to enable C11 features... unsupported
checking for cc -O option to enable C99 features... unsupported
checking for cc -O option to enable C89 features... none needed
Then the compilation command fails:
cc -O -DHAVE_CONFIG_H -I. -I.. -g -c -o hello.o ../hello.c
"/usr/include/sys/feature_tests.h", line 341: #error: "Compiler or options
invalid; UNIX 03 and POSIX.1-2001 applications require the use of c99"
cc: acomp failed for ../hello.c
*** Error code 2
When I set CC="cc -O -xc99", then ./configure prints
checking whether the compiler supports GNU C... no
checking whether cc -O -xc99 accepts -g... yes
checking for cc -O -xc99 option to enable C11 features... unsupported
checking for cc -O -xc99 option to enable C99 features... none needed
and the compilation command succeeds:
cc -O -xc99 -DHAVE_CONFIG_H -I. -I.. -g -c -o hello.o ../hello.c
So, that is a workaround. But the point of the AC_PROG_CC_C99 macro is that
the autoconfiguration finds out about the '-xc99' by itself, isn't it?
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Sat 27 Feb 2021 09:05:03 PM CET Name: hello-c-2.69.tar.gz Size: 75KiB
By: haible
<http://savannah.gnu.org/support/download.php?file_id=50939>
-------------------------------------------------------
Date: Sat 27 Feb 2021 09:05:03 PM CET Name: hello-c-2.71.tar.gz Size: 75KiB
By: haible
<http://savannah.gnu.org/support/download.php?file_id=50940>
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