Build problems: mpfr, mpc

[Richard Biener]

On Fri, Aug 20, 2021 at 12:55 PM Arjen Markus <arjen.markus895@gmail.com> wrote:
>
> Okay, that solved that error, now I get:
>
> .... -Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi=2 -fdiagnostics-show-location=once -ffunction-sections -fdata-sections -frandom-seed=fs_ops.lo -fimplicit-templates -g -O2 -c ../../../../../../libstdc++-v3/src/c++17/fs_ops.cc -o fs_ops.o
> In file included from ../../../../../../libstdc++-v3/src/c++17/fs_ops.cc:58:
> ../../../../../../libstdc++-v3/src/c++17/../filesystem/ops-common.h: In function 'const char* std::filesystem::get_temp_directory_from_env(std::error_code&)':
> ../../../../../../libstdc++-v3/src/c++17/../filesystem/ops-common.h:601:25: error: '::secure_getenv' has not been declared
>   601 |         auto tmpdir = ::secure_getenv(env);
>       |                         ^~~~~~~~~~~~~
>
> and there is a weird subdirectory under the build directory:  gccd: - the colon cannot be part of a directory name under Windows. I guess this is my mistake, as I set the install directory to "d:/gfortran/work" - that should become "/cygdrive/d/gfortran/work". Easily fixed, but I do not know what to do about the first error.

Possibly secure_getenv is not available in cygwin and for some reason
AC_CHECK_FUNCS (secure_getenv) as done by
libstdc++ configury misdetects it and/or the use site has a different
set of includes.  Jonathan might know.

Note using cygwin (or mingw for that) might make GCC development more
painful than necessary. It might be
that using a WSL2 based setup is easier if you're stuck to a Windows
host.  Using Linux in a virtual machine
might be another option of course.

Richard.

> Regards,
>
> Arjen
>
> Op vr 20 aug. 2021 om 12:10 schreef Arjen Markus <arjen.markus895@gmail.com>:
>>
>>
>>
>> Op vr 20 aug. 2021 om 11:54 schreef Richard Biener:
>>>
>>>
>>>
>>> The easiest is probably to build them in-tree by means of
>>> executing ./contrib/download_prerequesites which will download
>>> and unpack them into your source tree.
>>>
>>
>> Well, I do have the libraries (source and all) and I copied the built libraries (that is the content of mpfr/,libs and mpc/.libs to the locations that are referred to in the link statement, so I assumed that would enable the linker to find them.
>>
>>> Other than that you are likely either missing some of the requirements
>>> or lack the appropriate --with-{gmp,mpc,mpfr}[-lib] configury.
>>>
>>
>> The odd thing is that the link statement as presented in the command window knows where to find the libraries. Here is the (hopefully) relevant part:
>>
>> g++ -std=c++11 -no-pie   -g -DIN_GCC     -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall
>>       (...)  ../libcpp/libcpp.a ../libdecnumber/libdecnumber.a  -L/cygdrive/d/gfortran/gcc/build-gcc/./gmp/.libs -L/cygdrive/d/gfortran/gcc/build-gcc/./mpfr/src/.libs -L/cygdrive/d/gfortran/gcc/build-gcc/./mpc/src/.libs -lmpc -lmpfr -lgmp   -L./../zlib -lz  libcommon.a ../libcpp/libcpp.a  -liconv ../libbacktrace/.libs/libbacktrace.a ../libiberty/libiberty.a ../libdecnumber/libdecnumber.a
>> /usr/lib/gcc/x86_64-pc-cygwin/10/../../../../x86_64-pc-cygwin/bin/ld: cannot find -lmpc
>> /usr/lib/gcc/x86_64-pc-cygwin/10/../../../../x86_64-pc-cygwin/bin/ld: cannot find -lmpc
>> /usr/lib/gcc/x86_64-pc-cygwin/10/../../../../x86_64-pc-cygwin/bin/ld: cannot find -lmpfr
>> /usr/lib/gcc/x86_64-pc-cygwin/10/../../../../x86_64-pc-cygwin/bin/ld: cannot find -lmpfr
>> /usr/lib/gcc/x86_64-pc-cygwin/10/../../../../x86_64-pc-cygwin/bin/ld: cannot find -lmpc
>> /usr/lib/gcc/x86_64-pc-cygwin/10/../../../../x86_64-pc-cygwin/bin/ld: cannot find -lmpfr
>>
>>
>>> What host operating system are you using?
>>>
>> Cygwin on Windows 10
>>
>> Oops, now that I copied the relevant bit of the link command, I see what I did wrong: the libraries are under mpfr/./libs, not mpfr/src/.libs (and ditto for mpc).
>>
>> Okay, trying again!
>>
>> Thanks for the reply. This ought to do it.
>>
>> Regards,
>>
>> Arjen