Fix MSVC PDBs and permit them to be disabled if required (#5710)

* Revert "Remove /Zi compiler flag for MSVC, release config"

This reverts commit 9e1de3ec6e.

* Allow MSVC PDB creation to be disabled

Turn off ASSIMP_INSTALL_PDB to disable PDB creation

* Whitespace cleanup

Assimp uses spaces in cmakelists, not tabs

---------

Co-authored-by: Kim Kulling <kimkulling@users.noreply.github.com>

CMakeLists.txt

@@ -154,7 +154,7 @@ IF (WIN32)
 
   IF(MSVC)
     OPTION( ASSIMP_INSTALL_PDB
-      "Install MSVC debug files."
+      "Create MSVC debug symbol files and add to Install target."
       ON )
     IF(NOT (MSVC_VERSION LESS 1900))
       # Multibyte character set has been deprecated since at least MSVC2015 (possibly earlier)
@@ -299,8 +299,13 @@ ELSEIF(MSVC)
   # supress warning for double to float conversion if Double precision is activated
   ADD_COMPILE_OPTIONS(/wd4244)
   SET(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /D_DEBUG /Zi /Od")
-  SET(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
+  # Allow user to disable PDBs
+  if(ASSIMP_INSTALL_PDB)
+    SET(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Zi")
     SET(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /DEBUG:FULL /PDBALTPATH:%_PDB% /OPT:REF /OPT:ICF")
+  elseif((GENERATOR_IS_MULTI_CONFIG) OR (CMAKE_BUILD_TYPE MATCHES Release))
+    message("-- MSVC PDB generation disabled. Release binary will not be debuggable.")
+  endif()
 ELSEIF (CMAKE_CXX_COMPILER_ID MATCHES "Clang" )
   IF(NOT ASSIMP_HUNTER_ENABLED)
     SET(CMAKE_POSITION_INDEPENDENT_CODE ON)