Fix MacOS linker deprecation, update README

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## Ex_Cldr_Collation v0.7.5
+
+This is the changelog for Cldr_collation v0.7.5 released on September 29th, 2024.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_collation/tags)
+
+### Bug fixes
+
+* Remove deprecated linker option `-undefined suppress` in favour of `-undefined dynamic_lookup` on MacOS.
+
+* Update README to illustrate how an installed `libicu` in the search path will take precendence over user the native `icucore` library.
+
 ## Ex_Cldr_Collation v0.7.4
 
 This is the changelog for Cldr_collation v0.7.4 released on September 25th, 2024.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_collation/tags)

README.md

@@ -15,7 +15,17 @@ This initial version uses only the "root" locale collator which is the [CLDR DUC
 
 ### Installation on MacOS
 
-On MacOS, the relevant headers are included in `ex_cldr_collation` and no additional installation is required.
+On MacOS, the relevant headers are included in `ex_cldr_collation` and no additional installation is required. The build process will link to the MacOX native `icucore` library.
+
+However it is also possible to use another installation of `libicu` if, for some reason, the native installation is not sufficiently up-to-date.  An installed `icu4c` will take precedence over the native `icucore` library. For example, the following will install `icu4c` (which includes `libicu`), and link it into the standard search path. When compiling, this installation will take precendence.
+
+```bash
+% brew install icu4c
+% brew link icu4c
+# Remove any old build of the NIF that may have been linked to the native icucore lib
+% rm ./deps/ex_cldr_collation/priv.ucol.so
+% mix deps.compile ex_cldr_collation
+```
 
 ### Installation on Linux
 

c_src/Makefile

@@ -16,11 +16,11 @@ ifeq ($(UNAME_SYS), Darwin)
 	ifeq ($(UNAME_ARCH), arm)
 		CC ?= cc
 		CFLAGS = -O3 -std=c99 -arch arm64 -Wall -Wmissing-prototypes
-		LDFLAGS = -arch arm64 -flat_namespace -undefined suppress
+		LDFLAGS = -arch arm64 -flat_namespace -undefined dynamic_lookup
 	else
 		CC ?= cc
 		CFLAGS = -O3 -std=c99 -arch x86_64 -Wall -Wmissing-prototypes
-		LDFLAGS = -arch x86_64 -flat_namespace -undefined suppress
+		LDFLAGS = -arch x86_64 -flat_namespace -undefined dynamic_lookup
 	endif
 else ifeq ($(UNAME_SYS), FreeBSD)
 	CC ?= cc

mix.exs

@@ -1,7 +1,7 @@
 defmodule CldrCollation.MixProject do
   use Mix.Project
 
-  @version "0.7.4"
+  @version "0.7.5"
 
   def project do
     [