[math libs] Fix CMAKE_INSTALL_PREFIX init behavior on Win32.

[ScottTodd]

Summary

Per the guidance at https://cmake.org/cmake/help/latest/variable/CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT.html, CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT can be "used by project code to change the default without overriding a user-provided value".

Without these patches:

1. Our setting here is ignored:

   TheRock/cmake/therock_subproject.cmake

   Line 641 in bc656e4

   "-DCMAKE_INSTALL_PREFIX=${_stage_destination_dir}"

2. Subprojects install into the hardcoded C:/hipSDK path

3. Subprojects that depend on other subprojects fail to find expected files since they are searching the wrong locations:

   [build] [hipFFT configure] CMake Error at D:/projects/TheRock/cmake/therock_subproject_dep_provider.cmake:51 (find_package):
   [build] [hipFFT configure]   Could not find a package configuration file provided by "rocfft" with any
   [build] [hipFFT configure]   of the following names:
   [build] [hipFFT configure]
   [build] [hipFFT configure]     rocfftConfig.cmake
   [build] [hipFFT configure]     rocfft-config.cmake
   

   In that case, C:\hipSDK\lib\cmake\rocfft\rocfft-config.cmake exists but TheRock\build\math-libs\rocFFT\dist\lib\cmake\rocfft\rocfft-config.cmake does not.

Link to patch

See #340

Sent to subprojects

• Fix CMAKE_INSTALL_PREFIX init behavior on Win32. hipFFT#129
• Fix CMAKE_INSTALL_PREFIX init behavior on Win32. rocFFT#549
• Fix CMAKE_INSTALL_PREFIX init behavior on Win32. rocSPARSE#448
• Fix CMAKE_INSTALL_PREFIX init behavior on Win32. rocSOLVER#928
• Fix CMAKE_INSTALL_PREFIX init behavior on Win32. hipSPARSE#598
• Fix CMAKE_INSTALL_PREFIX init behavior on Win32. hipSOLVER#386

No PRs sent yet

• hipBLAS-common
• hipBLAS
• rocBLAS

[ScottTodd]

Looks like I missed some math-libs/BLAS sub-projects. They will need similar patches from

if (WIN32)
  SET( CMAKE_INSTALL_PREFIX "C:/hipSDK" CACHE PATH "Install path" FORCE )

to

if (WIN32)
  if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
    SET( CMAKE_INSTALL_PREFIX "C:/hipSDK" CACHE PATH "Install path" FORCE )
  endif()