dllGatherer

Console application that finds .dll files required for an executable to run properly and copies them to the executable directory. It doesn't replace existing files.

Compilation

Requires Qt library.

Run (in ddlGatherer source directory or pointing to it):

qmake

and then:

make

Although it solves the issue for other executables, this program itself suffers it so it requires a first time manual setup, in my local setup the list of files is:
libgcc_s_seh-1.dll (comes with mingw C/C++ compiler)
libicudt58.dll (ICU, comes with Qt by default)
libicuin58.dll (ICU, comes with Qt by default)
libicuuc58.dll (ICU, comes with Qt by default)
libstdc++-6.dll (comes with mingw C/C++ compiler)
libwinpthread-1.dll (comes with mingw C/C++ compiler)
Qt5Core.dll (Qt)
zlib1.dll (zlib, comes with Qt by default)
The files must be in the same directory as the dllGatherer executable or in one of the PATH directories. Some of the files might be optional, like the libicu* ones because the local installed Qt library doesn't have ICU.
If it still complains about needing dlls use a program like cygcheck.exe, Cygwin or Msys2 install it, or search for a "dependency walker" program to find the remaining.

"config.json" (required in the same directory) structure-example

{
  "cygcheckPath": "H:\\msys64\\usr\\bin\\cygcheck.exe"
  , "cygcheckDependencyNotFoundError": "cygcheck: track_down: could not find "
  , "windeployqtPath": "H:\\msys64\\mingw64\\bin\\windeployqt.exe"
  , "includeDllPaths": ["H:\\msys64\\mingw64\\bin"]
  , "excludeDllPaths": ["C:\\Program Files (x86)\\gtk-3.8.1", "H:\\FreeArc\\bin"]
}

"cygcheckPath" mandatory, cygcheck executable path or anything that outputs like it

"cygcheckDependencyNotFoundError" optional, defaults to "cygcheck: track_down: could not find " (the default error when cygcheck can't find a dll), this message is parsed to get the dll afterwards.

"windeployqtPath" optional

"includeDllPaths" optional, additional directories to search .dll files, by default dllGatherer searches in the PATH directories for dlls

"excludeDllPaths" optional, there might be undesired PATH directories to find/copy dlls from

Command line usage

dllGatherer.exe [another exe path]

File explorer usage

Drag and drop the target executable into dllGatherer.exe

Considerations

Cygcheck doesn't know/care about the dll files architecture so it can mix x86-64 with x86, making the target executable fail to run even with all the required dll in its path.