race condition in AC_PROG_CC?

[Bruno Haible]

Hi,

Just got this error message while executing gettext's configure (built with
autoconf-2.64) on Cygwin 1.5.25:


$ ./configure --prefix=/usr/local/cygwin CPPFLAGS="-I/usr/local/cygwin/include 
-Wall" LDFLAGS="-L/usr/local/cygwin/lib" --enable-shared
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking build system type... i686-pc-cygwin
checking host system type... i686-pc-cygwin
configure: creating ./config.status
config.status: creating Makefile
config.status: creating gnulib-local/Makefile
=== configuring in autoconf-lib-link 
(/home/bruno/gettext-0.18-pre1-cygwin-shared/autoconf-lib-link)
configure: running /bin/sh ./configure --disable-option-checking 
'--prefix=/usr/local/cygwin'  'CPPFLAGS=-I/usr/local/cygwin/include -Wall' 
'LDFLAGS=-L/usr/local/cygwin/lib' '--enable-shared' --cache-file=/dev/null 
--srcdir=.
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking for gcc... gcc
checking for C compiler default output file name... 
sed: can't read conftest.c: No such file or directory
configure: error: in 
`/home/bruno/gettext-0.18-pre1-cygwin-shared/autoconf-lib-link':
configure: error: C compiler cannot create executables
See `config.log' for more details.
configure: error: ./configure failed for autoconf-lib-link


The autoconf-lib-link/config.log contains this snippet:


## ----------- ##
## Core tests. ##
## ----------- ##

configure:3112: gcc  -I/usr/local/cygwin/include -Wall -L/usr/local/cygwin/lib 
conftest.c  >&5
gcc: conftest.c: No such file or directory
gcc: no input files
configure:3116: $? = 1
configure:3153: result:
configure: failed program was:
configure:3159: error: in 
`/home/bruno/gettext-0.18-pre1-cygwin-shared/autoconf-lib-link':
configure:3163: error: C compiler cannot create executables
See `config.log' for more details.


When I retried this same command, it worked fine. At the moment when it failed,
I was running 4 different configure scripts (each in its own separate directory)
in parallel.

I cannot believe that Cygwin would mix up things when creating two conftest.c
files in different directories at the same time. So is it a race condition in
the configure expansion of AC_PROG_CC?

When a Cygwin machine is overloaded, the symptoms are usually different:
  513776218 [main] sh 7548 fork: child -1 - died waiting for longjmp before 
initialization, retry -1, exit code 0xC0000142, errno 11
  ./configure: fork: Resource temporarily unavailable
and similar. (I tested this by running 100 configures in parallel.)

Bruno