[MacPorts] #60896: cmake @3.18.0_1: Unable to find MacPorts zlib

[MacPorts]

#60896: cmake @3.18.0_1: Unable to find MacPorts zlib
------------------------+---------------------------
 Reporter:  jasonliu--  |      Owner:  (none)
     Type:  defect      |     Status:  new
 Priority:  Normal      |  Milestone:
Component:  ports       |    Version:
 Keywords:              |       Port:  cmake openvdb
------------------------+---------------------------
 When trying to install `openvdb @7.0.0`, openvdb's CMake file will call
 the `FindZLIB` module to locate zlib. However, it's currently failing on
 my machine because the zlib that the cmake module is finding is the
 ancient macOS one located at `/usr/lib/libz.dylib` (zlib version 1.2.5).
 Even if the MacPorts zlib is installed (version 1.2.11), the cmake module
 isn't seeing it. It's causing the following error to be generated:

 {{{
 :info:configure CMake Error at
 /opt/local/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:165
 (message):
 :info:configure   Could NOT find ZLIB: Found unsuitable version "1.2.5",
 but required is at
 :info:configure   least "1.2.7" (found //usr/lib/libz.dylib)
 :info:configure Call Stack (most recent call first):
 :info:configure
 /opt/local/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:456
 (_FPHSA_FAILURE_MESSAGE)
 :info:configure   /opt/local/share/cmake-3.18/Modules/FindZLIB.cmake:115
 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
 :info:configure   openvdb/CMakeLists.txt:80 (find_package)
 }}}

 My system's info:
 * macOS 10.11.6 15G22010
 * Xcode 8.2.1 8C1002
 * `port installed | grep zlib` : `zlib @1.2.11_0 (active)`
 * `port installed | grep cmake` : `cmake @3.18.0_1 (active)`

 I didn't encounter this issue when installing `openvdb` on a "brand new"
 MacPorts machine (i.e. MacPorts had just been newly installed on it a few
 minutes before, and thus had no previously installed ports, etc.). This
 new machine had macOS 10.15 Catalina and Xcode 11.5. I'm not sure whether
 that's because the `/usr/lib/libz.dylib` is a new enough version of zlib
 that it's not generating the error, or something else. (I no longer have
 access to the 10.15 machine, so the previous sentence is just speculation
 on my part.)

 Also, one more observation. If you take a look at the log, the messages
 from just before the error I quoted above show that other cmake modules
 are able to see MacPorts ports, and so seems to indicate that the problem
 appears to be specific to just zlib, and not all cmake modules.

 {{{
 :info:configure -- ----------------------------------------------------
 :info:configure -- ------------- Configuring OpenVDBCore --------------
 :info:configure -- ----------------------------------------------------
 :info:configure -- Found PkgConfig: /opt/local/bin/pkg-config (found
 version "0.29.2")
 :info:configure -- Found IlmBase: /opt/local/include/OpenEXR (found
 suitable version "2.3", minimum required is "2.2") found components: Half
 :info:configure -- Found TBB: /opt/local/include (found suitable version
 "2020.3", minimum required is "2017.0") found components: tab
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/60896>
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