build(deps): add zlib build recipe

src/cmake/build_ZLIB.cmake

@@ -0,0 +1,24 @@
+# Copyright Contributors to the OpenImageIO project.
+# SPDX-License-Identifier: Apache-2.0
+# https://github.com/AcademySoftwareFoundation/OpenImageIO
+
+######################################################################
+# ZLIB by hand!
+######################################################################
+
+set_cache (ZLIB_BUILD_VERSION 1.3.1 "ZLIB version for local builds")
+set (ZLIB_GIT_REPOSITORY "https://github.com/madler/zlib")
+set (ZLIB_GIT_TAG "v${ZLIB_BUILD_VERSION}")
+
+build_dependency_with_cmake(ZLIB
+    VERSION         ${ZLIB_BUILD_VERSION}
+    GIT_REPOSITORY  ${ZLIB_GIT_REPOSITORY}
+    GIT_TAG         ${ZLIB_GIT_TAG}
+    )
+
+# Set some things up that we'll need for a subsequent find_package to work
+set (ZLIB_ROOT ${ZLIB_INSTALL_DIR})
+
+# Signal to caller that we need to find again at the installed location
+set (ZLIB_REFIND TRUE)
+set (ZLIB_VERSION ${ZLIB_BUILD_VERSION})