[build2] "error: failed to extract C++ header search paths"

[David Cohoe]

Hello,

I recently started using build2, initially on linux, and it's worked
well.  However, I tried installing it on windows 10 with mingw64, and
it doesn't work.  I made a simple hello world program and a simple
buildfile to build it (from the first example on the online
documentation), and when I try to run the build system it says:


error: failed to extract C++ header search paths
  info: command line: g++ -x c++ -v -E -


This is the output of g++ -x c++ -v -E -


Reading specs from C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/specs
COLLECT_GCC=g++
Target: x86_64-w64-mingw32
Configured with: ../../../src/gcc-8.1.0/configure
--host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32
--target=x86_64-w64-mingw32 --prefix=/mingw64
--with-sysroot=/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64
--enable-shared --enable-static --disable-multilib
--enable-languages=c,c++,fortran,lto --enable-libstdcxx-time=yes
--enable-threads=posix --enable-libgomp --enable-libatomic
--enable-lto --enable-graphite --enable-checking=release
--enable-fully-dynamic-string --enable-version-specific-runtime-libs
--disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap
--disable-rpath --disable-win32-registry --disable-nls
--disable-werror --disable-symvers --with-gnu-as --with-gnu-ld
--with-arch=nocona --with-tune=core2 --with-libiconv
--with-system-zlib
--with-gmp=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-mpfr=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-mpc=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-isl=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-pkgversion='x86_64-posix-seh-rev0, Built by MinGW-W64 project'
--with-bugurl=https://sourceforge.net/projects/mingw-w64 CFLAGS='-O2
-pipe -fno-ident
-I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include
-I/c/mingw810/prerequisites/x86_64-zlib-static/include
-I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include'
CXXFLAGS='-O2 -pipe -fno-ident
-I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include
-I/c/mingw810/prerequisites/x86_64-zlib-static/include
-I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include'
CPPFLAGS=' -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include
-I/c/mingw810/prerequisites/x86_64-zlib-static/include
-I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include'
LDFLAGS='-pipe -fno-ident
-L/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/lib
-L/c/mingw810/prerequisites/x86_64-zlib-static/lib
-L/c/mingw810/prerequisites/x86_64-w64-mingw32-static/lib '
Thread model: posix
gcc version 8.1.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project)
COLLECT_GCC_OPTIONS='-v' '-E' '-shared-libgcc' '-mtune=core2' '-march=nocona'
 C:/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/8.1.0/cc1plus.exe -E
-quiet -v -iprefix C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/
-D_REENTRANT - -mtune=core2 -march=nocona -I C:/mingw64/usr/include
ignoring duplicate directory
"C:/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++"
ignoring duplicate directory
"C:/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/x86_64-w64-mingw32"
ignoring duplicate directory
"C:/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/backward"
ignoring duplicate directory
"C:/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include"
ignoring nonexistent directory
"C:/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64C:/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../include"
ignoring duplicate directory
"C:/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed"
ignoring duplicate directory
"C:/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include"
ignoring nonexistent directory
"C:/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/mingw/include"
#include "..." search starts here:
#include <...> search starts here:
 C:/mingw64/usr/include
 C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++
 C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/x86_64-w64-mingw32
 C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/backward
 C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include
 C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed
 C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include
End of search list.


I had to Ctrl+C out of this, which I hope is okay.  Something
interesting I noticed when trying to copy this is that when I do "g++
-x c++ -v -E - 2>tmp", this is the contents of tmp:


Reading specs from C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/specs
COLLECT_GCC=g++
Target: x86_64-w64-mingw32
Configured with: ../../../src/gcc-8.1.0/configure
--host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32
--target=x86_64-w64-mingw32 --prefix=/mingw64
--with-sysroot=/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64
--enable-shared --enable-static --disable-multilib
--enable-languages=c,c++,fortran,lto --enable-libstdcxx-time=yes
--enable-threads=posix --enable-libgomp --enable-libatomic
--enable-lto --enable-graphite --enable-checking=release
--enable-fully-dynamic-string --enable-version-specific-runtime-libs
--disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap
--disable-rpath --disable-win32-registry --disable-nls
--disable-werror --disable-symvers --with-gnu-as --with-gnu-ld
--with-arch=nocona --with-tune=core2 --with-libiconv
--with-system-zlib
--with-gmp=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-mpfr=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-mpc=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-isl=/c/mingw810/prerequisites/x86_64-w64-mingw32-static
--with-pkgversion='x86_64-posix-seh-rev0, Built by MinGW-W64 project'
--with-bugurl=https://sourceforge.net/projects/mingw-w64 CFLAGS='-O2
-pipe -fno-ident
-I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include
-I/c/mingw810/prerequisites/x86_64-zlib-static/include
-I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include'
CXXFLAGS='-O2 -pipe -fno-ident
-I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include
-I/c/mingw810/prerequisites/x86_64-zlib-static/include
-I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include'
CPPFLAGS=' -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include
-I/c/mingw810/prerequisites/x86_64-zlib-static/include
-I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include'
LDFLAGS='-pipe -fno-ident
-L/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/lib
-L/c/mingw810/prerequisites/x86_64-zlib-static/lib
-L/c/mingw810/prerequisites/x86_64-w64-mingw32-static/lib '
Thread model: posix
gcc version 8.1.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project)
COLLECT_GCC_OPTIONS='-v' '-E' '-shared-libgcc' '-mtune=core2' '-march=nocona'
 C:/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/8.1.0/cc1plus.exe -E
-quiet -v -iprefix C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/
-D_REENTRANT - -mtune=core2 -march=nocona -I C:/mingw64/usr/include


I don't know why, but the include paths are not there.  Am I doing
something wrong, or is this a bug in build2?