configure fails on cygwin/msys without g++ installed

[GoogleCodeExporter]

v0.4.1-493-ga6c1593

What steps will reproduce the problem?
1. Install cygwin / msys with a minimal build environment (gcc, but not g++)
2. ./configure
3.

What is the expected output? What do you see instead?

Configuration should pass, but since anim_diff which requires c++ was added [1] 
AC_PROG_CXX will fail as it finds a CC.exe (linked to gcc), but fails when 
trying to use that to preprocess a c++ file.

Ideally since this is an optional tool configuration would still complete.

To workaround the issue one can do:
$ ./configure CXX=g++

which will fail the c++ compiler check a bit more gracefully.

[1] acd7b5a Introduce a test tool anim_diff.

configure console output below, config.log attached.

checking build system type... x86_64-unknown-cygwin
checking host system type... x86_64-unknown-cygwin
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 whether make supports nested variables... yes
checking for style of include used by make... GNU
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.exe
checking for suffix of executables... .exe
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking whether gcc understands -c and -o together... yes
checking dependency style of gcc... gcc3
checking for ar... ar
checking the archiver (ar) interface... ar
configure: WARNING: Libtool does not cope well with whitespace in `pwd`
checking how to print strings... printf
checking for a sed that does not truncate output... /usr/bin/sed
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for fgrep... /usr/bin/grep -F
checking for ld used by gcc... /usr/x86_64-pc-cygwin/bin/ld.exe
checking if the linker (/usr/x86_64-pc-cygwin/bin/ld.exe) is GNU ld... yes
checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B
checking the name lister (/usr/bin/nm -B) interface... BSD nm
checking whether ln -s works... yes
checking the maximum length of command line arguments... 8192
checking whether the shell understands some XSI constructs... yes
checking whether the shell understands "+="... yes
checking how to convert x86_64-unknown-cygwin file names to 
x86_64-unknown-cygwin format... func_convert_file_noop
checking how to convert x86_64-unknown-cygwin file names to toolchain format... 
func_convert_file_noop
checking for /usr/x86_64-pc-cygwin/bin/ld.exe option to reload object files... 
-r
checking for objdump... objdump
checking how to recognize dependent libraries... file_magic ^x86 archive 
import|^x86 DLL
checking for dlltool... dlltool
checking how to associate runtime and link libraries... 
func_cygming_dll_for_implib
checking for archiver @FILE support... @
checking for strip... strip
checking for ranlib... ranlib
checking command to parse /usr/bin/nm -B output from gcc object... ok
checking for sysroot... no
checking for mt... no
checking if : is a manifest tool... no
checking how to run the C preprocessor... gcc -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking for dlfcn.h... yes
checking for objdir... .libs
checking if gcc supports -fno-rtti -fno-exceptions... no
checking for gcc option to produce PIC... -DDLL_EXPORT -DPIC
checking if gcc PIC flag -DDLL_EXPORT -DPIC works... yes
checking if gcc static flag -static works... yes
checking if gcc supports -c -o file.o... yes
checking if gcc supports -c -o file.o... (cached) yes
checking whether the gcc linker (/usr/x86_64-pc-cygwin/bin/ld.exe) supports 
shared libraries... yes
checking whether -lc should be explicitly linked in... yes
checking dynamic linker characteristics... Win32 ld.exe
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... yes
checking for g++... no
checking for c++... no
checking for gpp... no
checking for aCC... no
checking for CC... CC
checking whether we are using the GNU C++ compiler... no
checking whether CC accepts -g... no
checking dependency style of CC... gcc3
checking how to run the C++ preprocessor... /lib/cpp
configure: error: in `[...]':
configure: error: C++ preprocessor "/lib/cpp" fails sanity check
See `config.log' for more details

Original issue reported on code.google.com by jz...@google.com on 8 May 2015 at 9:41

Attachments:

• config.log

[GoogleCodeExporter]

Can't we add a compile test that tries to compile a C++-specific one-line 
program?

Like:

int main() {
#ifdef (__cpluscplus__)
  return 0;
#else
 #error not a C++ compiler!
#endif
}

or with __GNUG__, or equivalent...

Original comment by pascal.m...@gmail.com on 13 May 2015 at 6:53

[GoogleCodeExporter]

there is one. this failure precedes that as part of the AC_PROG_CXX macro.

Original comment by jz...@google.com on 13 May 2015 at 6:55