[stb] Modify port file to not create empty dirs or copy the test dir

ports/stb/portfile.cmake

@@ -12,5 +12,6 @@ file(COPY ${CURRENT_BUILDTREES_DIR}/src/stb/README.md DESTINATION ${CURRENT_PACK
 file(RENAME ${CURRENT_PACKAGES_DIR}/share/stb/README.md ${CURRENT_PACKAGES_DIR}/share/stb/copyright)
 
 # Copy the stb header files
-file(INSTALL ${CURRENT_BUILDTREES_DIR}/src/stb/ DESTINATION ${CURRENT_PACKAGES_DIR}/include FILES_MATCHING PATTERN "*.h")
+file(GLOB HEADER_FILES ${CURRENT_BUILDTREES_DIR}/src/stb/*.h)
+file(COPY ${HEADER_FILES} DESTINATION ${CURRENT_PACKAGES_DIR}/include)
 vcpkg_copy_pdbs()