On Windows, mysterious `.dll` appearing on end of various `-l` in config

[mohawk2]

I was able to repro this locally on Windows, and by editing Alien-PLplot-0.001\blib\lib\auto\share\dist\Alien-PLplot\_alien\alien.json to remove them, Alien::PLplot then worked.

Before:

   "libs" : "-LC:/(strawperl)/c/lib/PKGCON~1/../../lib -lplplot -lgd.dll -lpng.dll -lz.dll -ljpeg.dll -lfreetype.dll -lgdi32 -lcomdlg32 -lcsirocsa -lqsastime -LZ:/mingw64bit.830/lib/gcc/x86_64-w64-mingw32/8.3.0 -lstdc++.dll -LZ:/mingw64bit.830/x86_64-w64-mingw32/lib -lmingw32 -lgcc_s -lgcc -lmoldname -lmingwex -lpthread.dll -ladvapi32 -lshell32 -luser32 -lkernel32 -liconv ",

After:

   "libs" : "-LC:/(strawperl)/c/lib/PKGCON~1/../../lib -lplplot -lgd -lpng -lz -ljpeg -lfreetype -lgdi32 -lcomdlg32 -lcsirocsa -lqsastime -LZ:/mingw64bit.830/lib/gcc/x86_64-w64-mingw32/8.3.0 -lstdc++ -LZ:/mingw64bit.830/x86_64-w64-mingw32/lib -lmingw32 -lgcc_s -lgcc -lmoldname -lmingwex -lpthread -ladvapi32 -lshell32 -luser32 -lkernel32 -liconv ",

To summarise: .dll is getting added to the -llibname for:

• gd
• png
• z
• jpeg
• freetype
• stdc++

although the last one didn't prompt a complaint.

[mohawk2]

Also, in P:G:PLplot CI on Windows, it's saying:

  *** PLPLOT WARNING ***
  Unable to open cmap0 file cmap0_default.pal
  
  
  *** PLPLOT ERROR, IMMEDIATE EXIT ***
  Unable to either (1) open/find or (2) allocate memory for the font file

This may be unconnected to the previous thing.