Fftw build failed when open ENABLE_OPENMP

[LilyWangLL]

The version of fftw: 3.3.10
OS: Windows 11 x64 & Visual Studio 2022

I use vcpkg to install fftw3[openmp], it build failed on with the following errors. The solution from #120 could resolve these errors, but this could cause repeat their definitions in the DLL.

I also test this #142 (comment), but it still builds failed. cc @stevengj

[449/450] cmd.exe /C "cd . && "C:\Program Files\CMake\bin\cmake.exe" -E vs_link_dll --intdir=CMakeFiles\fftw3f_omp.dir --rc=C:\PROGRA~2\WI3CF2~1\10\bin\100183~1.0\x64\rc.exe --mt=C:\PROGRA~2\WI3CF2~1\10\bin\100183~1.0\x64\mt.exe --manifests  -- C:\PROGRA~2\MICROS~1\2019\COMMUN~1\VC\Tools\MSVC\1425~1.286\bin\Hostx64\x64\link.exe  CMakeFiles\fftw3f_omp.dir\threads\api.c.obj CMakeFiles\fftw3f_omp.dir\threads\conf.c.obj CMakeFiles\fftw3f_omp.dir\threads\ct.c.obj CMakeFiles\fftw3f_omp.dir\threads\dft-vrank-geq1.c.obj CMakeFiles\fftw3f_omp.dir\threads\f77api.c.obj CMakeFiles\fftw3f_omp.dir\threads\hc2hc.c.obj CMakeFiles\fftw3f_omp.dir\threads\rdft-vrank-geq1.c.obj CMakeFiles\fftw3f_omp.dir\threads\vrank-geq1-rdft2.c.obj CMakeFiles\fftw3f_omp.dir\threads\openmp.c.obj  /out:fftw3f_omp.dll /implib:fftw3f_omp.lib /pdb:fftw3f_omp.pdb /dll /version:3.0 /machine:x64 /debug /INCREMENTAL  fftw3f.lib  kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib  && cd ."
FAILED: fftw3f_omp.dll fftw3f_omp.lib 
cmd.exe /C "cd . && "C:\Program Files\CMake\bin\cmake.exe" -E vs_link_dll --intdir=CMakeFiles\fftw3f_omp.dir --rc=C:\PROGRA~2\WI3CF2~1\10\bin\100183~1.0\x64\rc.exe --mt=C:\PROGRA~2\WI3CF2~1\10\bin\100183~1.0\x64\mt.exe --manifests  -- C:\PROGRA~2\MICROS~1\2019\COMMUN~1\VC\Tools\MSVC\1425~1.286\bin\Hostx64\x64\link.exe  CMakeFiles\fftw3f_omp.dir\threads\api.c.obj CMakeFiles\fftw3f_omp.dir\threads\conf.c.obj CMakeFiles\fftw3f_omp.dir\threads\ct.c.obj CMakeFiles\fftw3f_omp.dir\threads\dft-vrank-geq1.c.obj CMakeFiles\fftw3f_omp.dir\threads\f77api.c.obj CMakeFiles\fftw3f_omp.dir\threads\hc2hc.c.obj CMakeFiles\fftw3f_omp.dir\threads\rdft-vrank-geq1.c.obj CMakeFiles\fftw3f_omp.dir\threads\vrank-geq1-rdft2.c.obj CMakeFiles\fftw3f_omp.dir\threads\openmp.c.obj  /out:fftw3f_omp.dll /implib:fftw3f_omp.lib /pdb:fftw3f_omp.pdb /dll /version:3.0 /machine:x64 /debug /INCREMENTAL  fftw3f.lib  kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib  && cd ."
LINK Pass 1: command "C:\PROGRA~2\MICROS~1\2019\COMMUN~1\VC\Tools\MSVC\1425~1.286\bin\Hostx64\x64\link.exe CMakeFiles\fftw3f_omp.dir\threads\api.c.obj CMakeFiles\fftw3f_omp.dir\threads\conf.c.obj CMakeFiles\fftw3f_omp.dir\threads\ct.c.obj CMakeFiles\fftw3f_omp.dir\threads\dft-vrank-geq1.c.obj CMakeFiles\fftw3f_omp.dir\threads\f77api.c.obj CMakeFiles\fftw3f_omp.dir\threads\hc2hc.c.obj CMakeFiles\fftw3f_omp.dir\threads\rdft-vrank-geq1.c.obj CMakeFiles\fftw3f_omp.dir\threads\vrank-geq1-rdft2.c.obj CMakeFiles\fftw3f_omp.dir\threads\openmp.c.obj /out:fftw3f_omp.dll /implib:fftw3f_omp.lib /pdb:fftw3f_omp.pdb /dll /version:3.0 /machine:x64 /debug /INCREMENTAL fftw3f.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib /MANIFEST /MANIFESTFILE:CMakeFiles\fftw3f_omp.dir/intermediate.manifest CMakeFiles\fftw3f_omp.dir/manifest.res" failed (exit code 1120) with the following output:
Microsoft (R) Incremental Linker Version 14.25.28611.0
Copyright (C) Microsoft Corporation.  All rights reserved.

   Creating library fftw3f_omp.lib and object fftw3f_omp.exp
api.c.obj : error LNK2019: unresolved external symbol fftwf_imax referenced in function fftwf_plan_with_nthreads
api.c.obj : error LNK2001: unresolved external symbol fftwf_mksolver_ct_hook
api.c.obj : error LNK2001: unresolved external symbol fftwf_mksolver_hc2hc_hook
conf.c.obj : error LNK2019: unresolved external symbol fftwf_solvtab_exec referenced in function fftwf_threads_conf_standard
ct.c.obj : error LNK2001: unresolved external symbol fftwf_dft_solve
dft-vrank-geq1.c.obj : error LNK2001: unresolved external symbol fftwf_dft_solve
vrank-geq1-rdft2.c.obj : error LNK2019: unresolved external symbol fftwf_ops_zero referenced in function applicable
ct.c.obj : error LNK2001: unresolved external symbol fftwf_ops_zero
dft-vrank-geq1.c.obj : error LNK2001: unresolved external symbol fftwf_ops_zero
hc2hc.c.obj : error LNK2001: unresolved external symbol fftwf_ops_zero
rdft-vrank-geq1.c.obj : error LNK2001: unresolved external symbol fftwf_ops_zero
vrank-geq1-rdft2.c.obj : error LNK2019: unresolved external symbol fftwf_ops_add2 referenced in function applicable
ct.c.obj : error LNK2001: unresolved external symbol fftwf_ops_add2
dft-vrank-geq1.c.obj : error LNK2001: unresolved external symbol fftwf_ops_add2
hc2hc.c.obj : error LNK2001: unresolved external symbol fftwf_ops_add2
rdft-vrank-geq1.c.obj : error LNK2001: unresolved external symbol fftwf_ops_add2

[garging]

I fixed almost all errors by adding IFFTW_EXTERN to function declarations except for fftwf_mksolver_hc2hc_hook... This function is exported at fftw3f.dll, but cannot be linked in fftw3f_omp.