Merge pull request #4898 from shaunrd0/zlib-nobuild

Don't build zlib if ASSIMP_BUILD_ZLIB=OFF

.github/workflows/ccpp.yml

@@ -99,7 +99,7 @@ jobs:
     - name: Set Windows specific CMake arguments
       if: contains(matrix.name, 'windows')
       id: windows_extra_cmake_args
-      run: echo "::set-output name=args::-DASSIMP_BUILD_ASSIMP_TOOLS=1 -DASSIMP_BUILD_ASSIMP_VIEW=1"
+      run: echo "::set-output name=args::-DASSIMP_BUILD_ASSIMP_TOOLS=1 -DASSIMP_BUILD_ASSIMP_VIEW=1 -DASSIMP_BUILD_ZLIB=1"
     
     - name: Set Hunter specific CMake arguments
       if: contains(matrix.name, 'hunter')

CMakeLists.txt

@@ -482,7 +482,11 @@ ELSE()
     FIND_PACKAGE(ZLIB)
   ENDIF()
 
-  IF( NOT ZLIB_FOUND )
+  IF ( NOT ZLIB_FOUND AND NOT ASSIMP_BUILD_ZLIB )
+    message( FATAL_ERROR
+      "Build configured with -DASSIMP_BUILD_ZLIB=OFF but unable to find zlib"
+    )
+  ELSEIF( NOT ZLIB_FOUND )
     MESSAGE(STATUS "compiling zlib from sources")
     INCLUDE(CheckIncludeFile)
     INCLUDE(CheckTypeSize)