In reply to Brian Inglis, with acknowledgement to Kevin Schnitzius for his
reply also.
There's nothing in my setup that I know of that would account for this odd
behavior. CMake is munging the paths tools in the configuration stage of
its operation. OK, point by point (much detail follows):
On Fri, Jul 18, 2025 at 7:36 PM Brian Inglis via Cygwin <cygwin@cygwin.com>
wrote:
> On 2025-07-18 16:14, Soren via Cygwin wrote:
> > Hello Cygwinstas,
> >
> > Cygwin root is C:\ix\cygwin, just so you know.
> >
> > This is the output I see: mintty screen dump:
> >
> > $ cmake -G"Unix Makefiles" C:/Users/somia/Downloads/libjpeg-turbo-3.1.1/
> > cmake -G"Unix Makefiles" C:/Users/somia/Downloads/libjpeg-turbo-3.1.1/
> > -- The C compiler identification is GNU 12.5.0
> > -- Detecting C compiler ABI info
> > -- Detecting C compiler ABI info - failed
> > -- Check for working C compiler: /c/ix/cygwin/bin/cc
> > -- Check for working C compiler: /c/ix/cygwin/bin/cc - broken
> > CMake Error at /usr/share/cmake/Modules/CMakeTestCCompiler.cmake:67
> (message):
> > The C compiler
> >
> > "/c/ix/cygwin/bin/cc"
> >
> > is not able to compile a simple test program.
> > It fails with the following output:
> > Change Dir:
> '/c/Users/somia/build/libjpeg-turbo/CMakeFiles/CMakeScratch/TryCompile-PYyzjN'
> >
> > Run Build Command(s): /usr/bin/cmake.exe -E env VERBOSE=1
> > /c/perl/c/bin/gmake.exe -f Makefile cmTC_de473/fast
> > C:/perl/c/bin/gmake -f CMakeFiles/cmTC_de473.dir/build.make
> > CMakeFiles/cmTC_de473.dir/build
> > gmake[1]: Entering directory
> >
> 'C:/Users/somia/build/libjpeg-turbo/CMakeFiles/CMakeScratch/TryCompile-PYyzjN'
> > Building C object CMakeFiles/cmTC_de473.dir/testCCompiler.c.o
> > /c/ix/cygwin/bin/cc -o
> > CMakeFiles/cmTC_de473.dir/testCCompiler.c.o -c
> >
> /c/Users/somia/build/libjpeg-turbo/CMakeFiles/CMakeScratch/TryCompile-PYyzjN/testCCompiler.c
> > /usr/bin/sh: /c/ix/cygwin/bin/cc: No such file or directory
> > gmake[1]: *** [CMakeFiles/cmTC_de473.dir/build.make:78:
> > CMakeFiles/cmTC_de473.dir/testCCompiler.c.o] Error 127
> > gmake[1]: Leaving directory
> >
> 'C:/Users/somia/build/libjpeg-turbo/CMakeFiles/CMakeScratch/TryCompile-PYyzjN'
> > gmake: *** [Makefile:127: cmTC_de473/fast] Error 2
> >
> >
> > CMake will not be able to correctly generate this project.
> > Call Stack (most recent call first):
> > CMakeLists.txt:16 (project)
> >
> > -- Configuring incomplete, errors occurred!
> >
> > If I clean out all cached data in my build dir and set `CC=/bin/gcc';
> > export CC' is get another error:
> >
> > cmake -G"Unix Makefiles" C:/Users/somia/Downloads/libjpeg-turbo-3.1.1/
> > CMake Error at /usr/share/cmake/Modules/CMakeDetermineCCompiler.cmake:49
> > (message):
> > Could not find compiler set in environment variable CC:
> > /bin/gcc.
> > Call Stack (most recent call first):
> > CMakeLists.txt:16 (project)
> >
> > CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage
> > -- Configuring incomplete, errors occurred!
> >
> > I hear people saying good things about CMake but this is maddening.
> > My cmake is newly installed in /usr/bin/cmake and is version 3.30.1
> >
> > I'm trying to build libjpeg-turbo as my pathnames above would suggest.
>
> Cygwin current cmake is 3.31.3.
> It looks like you are running a Windows cmake.
> Try:
>
> $ which -a cmake
> /usr/bin/cmake
>
Yes, that is my cmake, Brian. Here's what `cygcheck' says:
$ cygcheck -i --inst cmake
Fetching setup.ini from cygwin.com...
Installed package:
------------------
Name : cmake
Version : 3.28.3
Release : 1
Architecture: x86_64
Install Date: Fri Jul 18 13:18:25 2025
Size : 14383900 (14 M)
Categories : Devel
Source : cmake-3.28.3-1-src.tar.xz
Summary : Cross-platform makefile generation system
...
Cygcheck -i --curr says the current (latest) cmake is what I have:
Latest available package:
-------------------------
Name : cmake
Version : 3.28.3
Are you using a testing release of cmake, Brian?
I have two cmakes, according to which -a cmake:
which -a cmake
/usr/bin/cmake
/cygdrive/c/ix/msys64/usr/bin/cmake
/cygdrive/c/ix/msys64/usr/bin/cmake --version
cmake version 3.30.1
I don't know why or how, that msys64 path-element comes very near the end
of my PATH, but when I cited "3.30.1" as my cmake version in my initial
message, that must have been the one I was picking up. I am going to move
that msys cmake out and away just to make sure it isn't the one trying to
configure for me.
About gcc:
$ ls -Ggl /bin/cc
> lrwxrwxrwx 1 7 Aug 2 2024 /bin/cc -> gcc.exe
>
> I get the positive output corresponding to yours:
lrwxrwxrwx 1 7 Jul 18 13:18 /bin/cc -> gcc.exe*
Are you running from a Cygwin terminal+/-shell, did you run Cygwin.bat, or
> set
> up a DOS/cmd environment with Cygwin bin at the start of your PATH?
>
> I am running from the mintty terminal with bash from the shortcut set up
by cygwin setup.exe on my desktop, not a CMD shell or a DOS "box". My setup
is very standard ("bog ordinary" ;-) for Cygwin and I don't have this sort
of problem building other projects (for example, recently, libpng).
You should also be using Cygwin paths not DOS/Windows device paths, which
> may
> not work with Cygwin tools.
>
In my experience nearly all cygwin tools work with "mixed-mode" pathnames
which are <drive>:/a/path/to/anywhere, the only exception I've become aware
of is GnuPG (gpg).
I'm not sure why the path to the libjpeg-turbo source tree was specified as
a mixed-mode path, I was just in the flow of starting this new effort and
didn't notice that.
> If you want to work in the Windows environment and do Windows builds, try
> Msys2.
>
> --
> Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
> Thanks Brian, I appreciate your time.
-- Soren
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